version: bump snapshot

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

.gitignore

@@ -1,4 +1 @@
 wireguard-go
-vendor
-.gopath
-ireallywantobuildon_linux.go

Makefile

@@ -1,33 +1,19 @@
 PREFIX ?= /usr
 DESTDIR ?=
 BINDIR ?= $(PREFIX)/bin
-export GOPATH ?= $(CURDIR)/.gopath
 export GO111MODULE := on
 
 all: generate-version-and-build
 
-ifeq ($(shell go env GOOS)|$(wildcard .git),linux|)
-$(error Do not build this for Linux. Instead use the Linux kernel module. See wireguard.com/install/ for more info.)
-else ifeq ($(shell go env GOOS),linux)
-ireallywantobuildon_linux.go:
-	@printf "WARNING: This software is meant for use on non-Linux\nsystems. For Linux, please use the kernel module\ninstead. See wireguard.com/install/ for more info.\n\n" >&2
-	@printf 'package main\nconst UseTheKernelModuleInstead = 0xdeadbabe\n' > "$@"
-clean-ireallywantobuildon_linux.go:
-	@rm -f ireallywantobuildon_linux.go
-.PHONY: clean-ireallywantobuildon_linux.go
-clean: clean-ireallywantobuildon_linux.go
-wireguard-go: ireallywantobuildon_linux.go
-endif
-
 MAKEFLAGS += --no-print-directory
 
 generate-version-and-build:
 	@export GIT_CEILING_DIRECTORIES="$(realpath $(CURDIR)/..)" && \
 	tag="$$(git describe --dirty 2>/dev/null)" && \
-	ver="$$(printf 'package device\nconst WireGuardGoVersion = "%s"\n' "$$tag")" && \
-	[ "$$(cat device/version.go 2>/dev/null)" != "$$ver" ] && \
-	echo "$$ver" > device/version.go && \
-	git update-index --assume-unchanged device/version.go || true
+	ver="$$(printf 'package main\nconst Version = "%s"\n' "$$tag")" && \
+	[ "$$(cat version.go 2>/dev/null)" != "$$ver" ] && \
+	echo "$$ver" > version.go && \
+	git update-index --assume-unchanged version.go || true
 	@$(MAKE) wireguard-go
 
 wireguard-go: $(wildcard *.go) $(wildcard */*.go)
@@ -36,7 +22,10 @@ wireguard-go: $(wildcard *.go) $(wildcard */*.go)
 install: wireguard-go
 	@install -v -d "$(DESTDIR)$(BINDIR)" && install -v -m 0755 "$<" "$(DESTDIR)$(BINDIR)/wireguard-go"
 
+test:
+	go test -v ./...
+
 clean:
 	rm -f wireguard-go
 
-.PHONY: all clean install generate-version-and-build
+.PHONY: all clean test install generate-version-and-build

README.md

@@ -2,8 +2,6 @@
 
 This is an implementation of WireGuard in Go.
 
-***WARNING:*** This is a work in progress and not ready for prime time, with no official "releases" yet. It is extremely rough around the edges and leaves much to be desired. There are bugs and we are not yet in a position to make claims about its security. Beware.
-
 ## Usage
 
 Most Linux kernel WireGuard users are used to adding an interface with `ip link add wg0 type wireguard`. With wireguard-go, instead simply run:
@@ -20,7 +18,7 @@ To run wireguard-go without forking to the background, pass `-f` or `--foregroun
 $ wireguard-go -f wg0
 ```
 
-When an interface is running, you may use [`wg(8)`](https://git.zx2c4.com/WireGuard/about/src/tools/man/wg.8) to configure it, as well as the usual `ip(8)` and `ifconfig(8)` commands.
+When an interface is running, you may use [`wg(8)`](https://git.zx2c4.com/wireguard-tools/about/src/man/wg.8) to configure it, as well as the usual `ip(8)` and `ifconfig(8)` commands.
 
 To run with more logging you may set the environment variable `LOG_LEVEL=debug`.
 
@@ -28,7 +26,7 @@ To run with more logging you may set the environment variable `LOG_LEVEL=debug`.
 
 ### Linux
 
-This will run on Linux; however **YOU SHOULD NOT RUN THIS ON LINUX**. Instead use the kernel module; see the [installation page](https://www.wireguard.com/install/) for instructions.
+This will run on Linux; however you should instead use the kernel module, which is faster and better integrated into the OS. See the [installation page](https://www.wireguard.com/install/) for instructions.
 
 ### macOS
 
@@ -36,7 +34,7 @@ This runs on macOS using the utun driver. It does not yet support sticky sockets
 
 ### Windows
 
-It is currently a work in progress to strip out the beginnings of an experiment done with the OpenVPN tuntap driver and instead port to the new UWP APIs for tunnels. In other words, this does not *yet* work on Windows.
+This runs on Windows, but you should instead use it from the more [fully featured Windows app](https://git.zx2c4.com/wireguard-windows/about/), which uses this as a module.
 
 ### FreeBSD
 
@@ -48,7 +46,7 @@ This will run on OpenBSD. It does not yet support sticky sockets. Fwmark is mapp
 
 ## Building
 
-This requires an installation of [go](https://golang.org) ≥ 1.12.
+This requires an installation of [go](https://golang.org) ≥ 1.13.
 
 ```
 $ git clone https://git.zx2c4.com/wireguard-go
@@ -58,7 +56,7 @@ $ make
 
 ## License
 
-    Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+    Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
     
     Permission is hereby granted, free of charge, to any person obtaining a copy of
     this software and associated documentation files (the "Software"), to deal in

conn/boundif_android.go

@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+func (bind *nativeBind) PeekLookAtSocketFd4() (fd int, err error) {
+	sysconn, err := bind.ipv4.SyscallConn()
+	if err != nil {
+		return -1, err
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return -1, err
+	}
+	return
+}
+
+func (bind *nativeBind) PeekLookAtSocketFd6() (fd int, err error) {
+	sysconn, err := bind.ipv6.SyscallConn()
+	if err != nil {
+		return -1, err
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return -1, err
+	}
+	return
+}

conn/boundif_windows.go

@@ -1,9 +1,9 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"encoding/binary"
@@ -17,13 +17,13 @@ const (
 	sockoptIPV6_UNICAST_IF = 31
 )
 
-func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
+func (bind *nativeBind) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
 	/* MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros. */
 	bytes := make([]byte, 4)
 	binary.BigEndian.PutUint32(bytes, interfaceIndex)
 	interfaceIndex = *(*uint32)(unsafe.Pointer(&bytes[0]))
 
-	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	sysconn, err := bind.ipv4.SyscallConn()
 	if err != nil {
 		return err
 	}
@@ -36,11 +36,12 @@ func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
 	if err != nil {
 		return err
 	}
+	bind.blackhole4 = blackhole
 	return nil
 }
 
-func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
-	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
+func (bind *nativeBind) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
+	sysconn, err := bind.ipv6.SyscallConn()
 	if err != nil {
 		return err
 	}
@@ -53,5 +54,6 @@ func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
 	if err != nil {
 		return err
 	}
+	bind.blackhole6 = blackhole
 	return nil
 }

conn/conn.go

@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+// Package conn implements WireGuard's network connections.
+package conn
+
+import (
+	"errors"
+	"net"
+	"strings"
+)
+
+// A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
+//
+// A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
+// depending on the platform-specific implementation.
+type Bind interface {
+	// LastMark reports the last mark set for this Bind.
+	LastMark() uint32
+
+	// SetMark sets the mark for each packet sent through this Bind.
+	// This mark is passed to the kernel as the socket option SO_MARK.
+	SetMark(mark uint32) error
+
+	// ReceiveIPv6 reads an IPv6 UDP packet into b.
+	//
+	// It reports the number of bytes read, n,
+	// the packet source address ep,
+	// and any error.
+	ReceiveIPv6(b []byte) (n int, ep Endpoint, err error)
+
+	// ReceiveIPv4 reads an IPv4 UDP packet into b.
+	//
+	// It reports the number of bytes read, n,
+	// the packet source address ep,
+	// and any error.
+	ReceiveIPv4(b []byte) (n int, ep Endpoint, err error)
+
+	// Send writes a packet b to address ep.
+	Send(b []byte, ep Endpoint) error
+
+	// Close closes the Bind connection.
+	Close() error
+}
+
+// CreateBind creates a Bind bound to a port.
+//
+// The value actualPort reports the actual port number the Bind
+// object gets bound to.
+func CreateBind(port uint16) (b Bind, actualPort uint16, err error) {
+	return createBind(port)
+}
+
+// BindSocketToInterface is implemented by Bind objects that support being
+// tied to a single network interface. Used by wireguard-windows.
+type BindSocketToInterface interface {
+	BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
+	BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
+}
+
+// PeekLookAtSocketFd is implemented by Bind objects that support having their
+// file descriptor peeked at. Used by wireguard-android.
+type PeekLookAtSocketFd interface {
+	PeekLookAtSocketFd4() (fd int, err error)
+	PeekLookAtSocketFd6() (fd int, err error)
+}
+
+// An Endpoint maintains the source/destination caching for a peer.
+//
+//	dst : the remote address of a peer ("endpoint" in uapi terminology)
+//	src : the local address from which datagrams originate going to the peer
+type Endpoint interface {
+	ClearSrc()           // clears the source address
+	SrcToString() string // returns the local source address (ip:port)
+	DstToString() string // returns the destination address (ip:port)
+	DstToBytes() []byte  // used for mac2 cookie calculations
+	DstIP() net.IP
+	SrcIP() net.IP
+}
+
+func parseEndpoint(s string) (*net.UDPAddr, error) {
+	// ensure that the host is an IP address
+
+	host, _, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil, err
+	}
+	if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
+		// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
+		// trying to make sure with a small sanity test that this is a real IP address and
+		// not something that's likely to incur DNS lookups.
+		host = host[:i]
+	}
+	if ip := net.ParseIP(host); ip == nil {
+		return nil, errors.New("Failed to parse IP address: " + host)
+	}
+
+	// parse address and port
+
+	addr, err := net.ResolveUDPAddr("udp", s)
+	if err != nil {
+		return nil, err
+	}
+	ip4 := addr.IP.To4()
+	if ip4 != nil {
+		addr.IP = ip4
+	}
+	return addr, err
+}

conn/conn_default.go

@@ -2,14 +2,14 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
+	"errors"
 	"net"
-	"os"
 	"syscall"
 )
 
@@ -23,6 +23,8 @@ import (
 type nativeBind struct {
 	ipv4       *net.UDPConn
 	ipv6       *net.UDPConn
+	blackhole4 bool
+	blackhole6 bool
 }
 
 type NativeEndpoint net.UDPAddr
@@ -35,7 +37,7 @@ func CreateEndpoint(s string) (Endpoint, error) {
 	return (*NativeEndpoint)(addr), err
 }
 
-func (_ *NativeEndpoint) ClearSrc() {}
+func (*NativeEndpoint) ClearSrc() {}
 
 func (e *NativeEndpoint) DstIP() net.IP {
 	return (*net.UDPAddr)(e).IP
@@ -65,16 +67,12 @@ func (e *NativeEndpoint) SrcToString() string {
 }
 
 func listenNet(network string, port int) (*net.UDPConn, int, error) {
-
-	// listen
-
 	conn, err := net.ListenUDP(network, &net.UDPAddr{Port: port})
 	if err != nil {
 		return nil, 0, err
 	}
 
-	// retrieve port
-
+	// Retrieve port.
 	laddr := conn.LocalAddr()
 	uaddr, err := net.ResolveUDPAddr(
 		laddr.Network(),
@@ -86,31 +84,26 @@ func listenNet(network string, port int) (*net.UDPConn, int, error) {
 	return conn, uaddr.Port, nil
 }
 
-func extractErrno(err error) error {
-	opErr, ok := err.(*net.OpError)
-	if !ok {
-		return nil
-	}
-	syscallErr, ok := opErr.Err.(*os.SyscallError)
-	if !ok {
-		return nil
-	}
-	return syscallErr.Err
-}
-
-func CreateBind(uport uint16, device *Device) (Bind, uint16, error) {
+func createBind(uport uint16) (Bind, uint16, error) {
 	var err error
 	var bind nativeBind
+	var tries int
 
+again:
 	port := int(uport)
 
 	bind.ipv4, port, err = listenNet("udp4", port)
-	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
 		return nil, 0, err
 	}
 
 	bind.ipv6, port, err = listenNet("udp6", port)
-	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+	if uport == 0 && err != nil && errors.Is(err, syscall.EADDRINUSE) && tries < 100 {
+		bind.ipv4.Close()
+		tries++
+		goto again
+	}
+	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
 		bind.ipv4.Close()
 		bind.ipv4 = nil
 		return nil, 0, err
@@ -133,6 +126,8 @@ func (bind *nativeBind) Close() error {
 	return err2
 }
 
+func (bind *nativeBind) LastMark() uint32 { return 0 }
+
 func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	if bind.ipv4 == nil {
 		return 0, nil, syscall.EAFNOSUPPORT
@@ -159,11 +154,17 @@ func (bind *nativeBind) Send(buff []byte, endpoint Endpoint) error {
 		if bind.ipv4 == nil {
 			return syscall.EAFNOSUPPORT
 		}
+		if bind.blackhole4 {
+			return nil
+		}
 		_, err = bind.ipv4.WriteToUDP(buff, (*net.UDPAddr)(nend))
 	} else {
 		if bind.ipv6 == nil {
 			return syscall.EAFNOSUPPORT
 		}
+		if bind.blackhole6 {
+			return nil
+		}
 		_, err = bind.ipv6.WriteToUDP(buff, (*net.UDPAddr)(nend))
 	}
 	return err

conn/conn_linux.go

@@ -2,19 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- *
- * This implements userspace semantics of "sticky sockets", modeled after
- * WireGuard's kernelspace implementation. This is more or less a straight port
- * of the sticky-sockets.c example code:
- * https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
- *
- * Currently there is no way to achieve this within the net package:
- * See e.g. https://github.com/golang/go/issues/17930
- * So this code is remains platform dependent.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"errors"
@@ -25,16 +16,11 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
-)
-
-const (
-	FD_ERR = -1
 )
 
 type IPv4Source struct {
-	src     [4]byte
-	ifindex int32
+	Src     [4]byte
+	Ifindex int32
 }
 
 type IPv6Source struct {
@@ -43,11 +29,16 @@ type IPv6Source struct {
 }
 
 type NativeEndpoint struct {
+	sync.Mutex
 	dst  [unsafe.Sizeof(unix.SockaddrInet6{})]byte
 	src  [unsafe.Sizeof(IPv6Source{})]byte
 	isV6 bool
 }
 
+func (endpoint *NativeEndpoint) Src4() *IPv4Source         { return endpoint.src4() }
+func (endpoint *NativeEndpoint) Dst4() *unix.SockaddrInet4 { return endpoint.dst4() }
+func (endpoint *NativeEndpoint) IsV6() bool                { return endpoint.isV6 }
+
 func (endpoint *NativeEndpoint) src4() *IPv4Source {
 	return (*IPv4Source)(unsafe.Pointer(&endpoint.src[0]))
 }
@@ -67,9 +58,8 @@ func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
 type nativeBind struct {
 	sock4    int
 	sock6    int
-	netlinkSock   int
-	netlinkCancel *rwcancel.RWCancel
 	lastMark uint32
+	closing  sync.RWMutex
 }
 
 var _ Endpoint = (*NativeEndpoint)(nil)
@@ -110,59 +100,34 @@ func CreateEndpoint(s string) (Endpoint, error) {
 	return nil, errors.New("Invalid IP address")
 }
 
-func createNetlinkRouteSocket() (int, error) {
-	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
-	if err != nil {
-		return -1, err
-	}
-	saddr := &unix.SockaddrNetlink{
-		Family: unix.AF_NETLINK,
-		Groups: uint32(1 << (unix.RTNLGRP_IPV4_ROUTE - 1)),
-	}
-	err = unix.Bind(sock, saddr)
-	if err != nil {
-		unix.Close(sock)
-		return -1, err
-	}
-	return sock, nil
-
-}
-
-func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
+func createBind(port uint16) (Bind, uint16, error) {
 	var err error
 	var bind nativeBind
 	var newPort uint16
+	var tries int
+	originalPort := port
 
-	bind.netlinkSock, err = createNetlinkRouteSocket()
-	if err != nil {
-		return nil, 0, err
-	}
-	bind.netlinkCancel, err = rwcancel.NewRWCancel(bind.netlinkSock)
-	if err != nil {
-		unix.Close(bind.netlinkSock)
-		return nil, 0, err
-	}
-
-	go bind.routineRouteListener(device)
-
-	// attempt ipv6 bind, update port if succesful
-
+again:
+	port = originalPort
+	// Attempt ipv6 bind, update port if successful.
 	bind.sock6, newPort, err = create6(port)
 	if err != nil {
 		if err != syscall.EAFNOSUPPORT {
-			bind.netlinkCancel.Cancel()
 			return nil, 0, err
 		}
 	} else {
 		port = newPort
 	}
 
-	// attempt ipv4 bind, update port if succesful
-
+	// Attempt ipv4 bind, update port if successful.
 	bind.sock4, newPort, err = create4(port)
 	if err != nil {
+		if originalPort == 0 && err == syscall.EADDRINUSE && tries < 100 {
+			unix.Close(bind.sock6)
+			tries++
+			goto again
+		}
 		if err != syscall.EAFNOSUPPORT {
-			bind.netlinkCancel.Cancel()
 			unix.Close(bind.sock6)
 			return nil, 0, err
 		}
@@ -170,14 +135,21 @@ func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
 		port = newPort
 	}
 
-	if bind.sock4 == FD_ERR && bind.sock6 == FD_ERR {
+	if bind.sock4 == -1 && bind.sock6 == -1 {
 		return nil, 0, errors.New("ipv4 and ipv6 not supported")
 	}
 
 	return &bind, port, nil
 }
 
+func (bind *nativeBind) LastMark() uint32 {
+	return bind.lastMark
+}
+
 func (bind *nativeBind) SetMark(value uint32) error {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	if bind.sock6 != -1 {
 		err := unix.SetsockoptInt(
 			bind.sock6,
@@ -208,35 +180,40 @@ func (bind *nativeBind) SetMark(value uint32) error {
 	return nil
 }
 
-func closeUnblock(fd int) error {
-	// shutdown to unblock readers and writers
-	unix.Shutdown(fd, unix.SHUT_RDWR)
-	return unix.Close(fd)
-}
-
 func (bind *nativeBind) Close() error {
-	var err1, err2, err3 error
+	var err1, err2 error
+	bind.closing.RLock()
 	if bind.sock6 != -1 {
-		err1 = closeUnblock(bind.sock6)
+		unix.Shutdown(bind.sock6, unix.SHUT_RDWR)
 	}
 	if bind.sock4 != -1 {
-		err2 = closeUnblock(bind.sock4)
+		unix.Shutdown(bind.sock4, unix.SHUT_RDWR)
 	}
-	err3 = bind.netlinkCancel.Cancel()
+	bind.closing.RUnlock()
+	bind.closing.Lock()
+	if bind.sock6 != -1 {
+		err1 = unix.Close(bind.sock6)
+		bind.sock6 = -1
+	}
+	if bind.sock4 != -1 {
+		err2 = unix.Close(bind.sock4)
+		bind.sock4 = -1
+	}
+	bind.closing.Unlock()
 
 	if err1 != nil {
 		return err1
 	}
-	if err2 != nil {
 	return err2
-	}
-	return err3
 }
 
 func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	var end NativeEndpoint
 	if bind.sock6 == -1 {
-		return 0, nil, syscall.EAFNOSUPPORT
+		return 0, nil, NetErrClosed
 	}
 	n, err := receive6(
 		bind.sock6,
@@ -247,9 +224,12 @@ func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 }
 
 func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	var end NativeEndpoint
 	if bind.sock4 == -1 {
-		return 0, nil, syscall.EAFNOSUPPORT
+		return 0, nil, NetErrClosed
 	}
 	n, err := receive4(
 		bind.sock4,
@@ -260,15 +240,18 @@ func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 }
 
 func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	nend := end.(*NativeEndpoint)
 	if !nend.isV6 {
 		if bind.sock4 == -1 {
-			return syscall.EAFNOSUPPORT
+			return NetErrClosed
 		}
 		return send4(bind.sock4, nend, buff)
 	} else {
 		if bind.sock6 == -1 {
-			return syscall.EAFNOSUPPORT
+			return NetErrClosed
 		}
 		return send6(bind.sock6, nend, buff)
 	}
@@ -277,10 +260,10 @@ func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
 func (end *NativeEndpoint) SrcIP() net.IP {
 	if !end.isV6 {
 		return net.IPv4(
-			end.src4().src[0],
-			end.src4().src[1],
-			end.src4().src[2],
-			end.src4().src[3],
+			end.src4().Src[0],
+			end.src4().Src[1],
+			end.src4().Src[2],
+			end.src4().Src[3],
 		)
 	} else {
 		return end.src6().src[:]
@@ -357,7 +340,7 @@ func create4(port uint16) (int, uint16, error) {
 	)
 
 	if err != nil {
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	addr := unix.SockaddrInet4{
@@ -367,15 +350,6 @@ func create4(port uint16) (int, uint16, error) {
 	// set sockopts and bind
 
 	if err := func() error {
-		if err := unix.SetsockoptInt(
-			fd,
-			unix.SOL_SOCKET,
-			unix.SO_REUSEADDR,
-			1,
-		); err != nil {
-			return err
-		}
-
 		if err := unix.SetsockoptInt(
 			fd,
 			unix.IPPROTO_IP,
@@ -388,7 +362,12 @@ func create4(port uint16) (int, uint16, error) {
 		return unix.Bind(fd, &addr)
 	}(); err != nil {
 		unix.Close(fd)
-		return FD_ERR, 0, err
+		return -1, 0, err
+	}
+
+	sa, err := unix.Getsockname(fd)
+	if err == nil {
+		addr.Port = sa.(*unix.SockaddrInet4).Port
 	}
 
 	return fd, uint16(addr.Port), err
@@ -405,7 +384,7 @@ func create6(port uint16) (int, uint16, error) {
 	)
 
 	if err != nil {
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	// set sockopts and bind
@@ -415,16 +394,6 @@ func create6(port uint16) (int, uint16, error) {
 	}
 
 	if err := func() error {
-
-		if err := unix.SetsockoptInt(
-			fd,
-			unix.SOL_SOCKET,
-			unix.SO_REUSEADDR,
-			1,
-		); err != nil {
-			return err
-		}
-
 		if err := unix.SetsockoptInt(
 			fd,
 			unix.IPPROTO_IPV6,
@@ -447,7 +416,12 @@ func create6(port uint16) (int, uint16, error) {
 
 	}(); err != nil {
 		unix.Close(fd)
-		return FD_ERR, 0, err
+		return -1, 0, err
+	}
+
+	sa, err := unix.Getsockname(fd)
+	if err == nil {
+		addr.Port = sa.(*unix.SockaddrInet6).Port
 	}
 
 	return fd, uint16(addr.Port), err
@@ -467,12 +441,14 @@ func send4(sock int, end *NativeEndpoint, buff []byte) error {
 			Len:   unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr,
 		},
 		unix.Inet4Pktinfo{
-			Spec_dst: end.src4().src,
-			Ifindex:  end.src4().ifindex,
+			Spec_dst: end.src4().Src,
+			Ifindex:  end.src4().Ifindex,
 		},
 	}
 
+	end.Lock()
 	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+	end.Unlock()
 
 	if err == nil {
 		return nil
@@ -483,7 +459,9 @@ func send4(sock int, end *NativeEndpoint, buff []byte) error {
 	if err == unix.EINVAL {
 		end.ClearSrc()
 		cmsg.pktinfo = unix.Inet4Pktinfo{}
+		end.Lock()
 		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+		end.Unlock()
 	}
 
 	return err
@@ -512,7 +490,9 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 		cmsg.pktinfo.Ifindex = 0
 	}
 
+	end.Lock()
 	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+	end.Unlock()
 
 	if err == nil {
 		return nil
@@ -523,7 +503,9 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 	if err == unix.EINVAL {
 		end.ClearSrc()
 		cmsg.pktinfo = unix.Inet6Pktinfo{}
+		end.Lock()
 		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+		end.Unlock()
 	}
 
 	return err
@@ -531,7 +513,7 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 
 func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
-	// contruct message header
+	// construct message header
 
 	var cmsg struct {
 		cmsghdr unix.Cmsghdr
@@ -554,8 +536,8 @@ func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 	if cmsg.cmsghdr.Level == unix.IPPROTO_IP &&
 		cmsg.cmsghdr.Type == unix.IP_PKTINFO &&
 		cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo {
-		end.src4().src = cmsg.pktinfo.Spec_dst
-		end.src4().ifindex = cmsg.pktinfo.Ifindex
+		end.src4().Src = cmsg.pktinfo.Spec_dst
+		end.src4().Ifindex = cmsg.pktinfo.Ifindex
 	}
 
 	return size, nil
@@ -563,7 +545,7 @@ func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
 func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
-	// contruct message header
+	// construct message header
 
 	var cmsg struct {
 		cmsghdr unix.Cmsghdr
@@ -592,156 +574,3 @@ func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
 	return size, nil
 }
-
-func (bind *nativeBind) routineRouteListener(device *Device) {
-	type peerEndpointPtr struct {
-		peer     *Peer
-		endpoint *Endpoint
-	}
-	var reqPeer map[uint32]peerEndpointPtr
-	var reqPeerLock sync.Mutex
-
-	defer unix.Close(bind.netlinkSock)
-
-	for msg := make([]byte, 1<<16); ; {
-		var err error
-		var msgn int
-		for {
-			msgn, _, _, _, err = unix.Recvmsg(bind.netlinkSock, msg[:], nil, 0)
-			if err == nil || !rwcancel.RetryAfterError(err) {
-				break
-			}
-			if !bind.netlinkCancel.ReadyRead() {
-				return
-			}
-		}
-		if err != nil {
-			return
-		}
-
-		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
-
-			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
-
-			if uint(hdr.Len) > uint(len(remain)) {
-				break
-			}
-
-			switch hdr.Type {
-			case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
-				if hdr.Seq <= MaxPeers && hdr.Seq > 0 {
-					if uint(len(remain)) < uint(hdr.Len) {
-						break
-					}
-					if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
-						attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
-						for {
-							if uint(len(attr)) < uint(unix.SizeofRtAttr) {
-								break
-							}
-							attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
-							if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
-								break
-							}
-							if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
-								ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
-								reqPeerLock.Lock()
-								if reqPeer == nil {
-									reqPeerLock.Unlock()
-									break
-								}
-								pePtr, ok := reqPeer[hdr.Seq]
-								reqPeerLock.Unlock()
-								if !ok {
-									break
-								}
-								pePtr.peer.Lock()
-								if &pePtr.peer.endpoint != pePtr.endpoint {
-									pePtr.peer.Unlock()
-									break
-								}
-								if uint32(pePtr.peer.endpoint.(*NativeEndpoint).src4().ifindex) == ifidx {
-									pePtr.peer.Unlock()
-									break
-								}
-								pePtr.peer.endpoint.(*NativeEndpoint).ClearSrc()
-								pePtr.peer.Unlock()
-							}
-							attr = attr[attrhdr.Len:]
-						}
-					}
-					break
-				}
-				reqPeerLock.Lock()
-				reqPeer = make(map[uint32]peerEndpointPtr)
-				reqPeerLock.Unlock()
-				go func() {
-					device.peers.RLock()
-					i := uint32(1)
-					for _, peer := range device.peers.keyMap {
-						peer.RLock()
-						if peer.endpoint == nil || peer.endpoint.(*NativeEndpoint) == nil {
-							peer.RUnlock()
-							continue
-						}
-						if peer.endpoint.(*NativeEndpoint).isV6 || peer.endpoint.(*NativeEndpoint).src4().ifindex == 0 {
-							peer.RUnlock()
-							break
-						}
-						nlmsg := struct {
-							hdr     unix.NlMsghdr
-							msg     unix.RtMsg
-							dsthdr  unix.RtAttr
-							dst     [4]byte
-							srchdr  unix.RtAttr
-							src     [4]byte
-							markhdr unix.RtAttr
-							mark    uint32
-						}{
-							unix.NlMsghdr{
-								Type:  uint16(unix.RTM_GETROUTE),
-								Flags: unix.NLM_F_REQUEST,
-								Seq:   i,
-							},
-							unix.RtMsg{
-								Family:  unix.AF_INET,
-								Dst_len: 32,
-								Src_len: 32,
-							},
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_DST,
-							},
-							peer.endpoint.(*NativeEndpoint).dst4().Addr,
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_SRC,
-							},
-							peer.endpoint.(*NativeEndpoint).src4().src,
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_MARK,
-							},
-							uint32(bind.lastMark),
-						}
-						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
-						reqPeerLock.Lock()
-						reqPeer[i] = peerEndpointPtr{
-							peer:     peer,
-							endpoint: &peer.endpoint,
-						}
-						reqPeerLock.Unlock()
-						peer.RUnlock()
-						i++
-						_, err := bind.netlinkCancel.Write((*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
-						if err != nil {
-							break
-						}
-					}
-					device.peers.RUnlock()
-				}()
-			}
-			remain = remain[hdr.Len:]
-		}
-	}
-}

conn/mark_default.go

@@ -2,10 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 func (bind *nativeBind) SetMark(mark uint32) error {
 	return nil

conn/mark_unix.go

@@ -2,10 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"runtime"

conn/net_err_closed.go

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+import _ "unsafe"
+
+//TODO: replace this with net.ErrClosed for Go 1.16
+
+//go:linkname NetErrClosed internal/poll.ErrNetClosing
+var NetErrClosed error

device/alignment_test.go

@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+)
+
+func checkAlignment(t *testing.T, name string, offset uintptr) {
+	t.Helper()
+	if offset%8 != 0 {
+		t.Errorf("offset of %q within struct is %d bytes, which does not align to 64-bit word boundaries (missing %d bytes). Atomic operations will crash on 32-bit systems.", name, offset, 8-(offset%8))
+	}
+}
+
+// TestPeerAlignment checks that atomically-accessed fields are
+// aligned to 64-bit boundaries, as required by the atomic package.
+//
+// Unfortunately, violating this rule on 32-bit platforms results in a
+// hard segfault at runtime.
+func TestPeerAlignment(t *testing.T) {
+	var p Peer
+
+	typ := reflect.TypeOf(&p).Elem()
+	t.Logf("Peer type size: %d, with fields:", typ.Size())
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
+			field.Name,
+			field.Offset,
+			field.Type.Size(),
+			field.Type.Align(),
+		)
+	}
+
+	checkAlignment(t, "Peer.stats", unsafe.Offsetof(p.stats))
+	checkAlignment(t, "Peer.isRunning", unsafe.Offsetof(p.isRunning))
+}
+
+// TestDeviceAlignment checks that atomically-accessed fields are
+// aligned to 64-bit boundaries, as required by the atomic package.
+//
+// Unfortunately, violating this rule on 32-bit platforms results in a
+// hard segfault at runtime.
+func TestDeviceAlignment(t *testing.T) {
+	var d Device
+
+	typ := reflect.TypeOf(&d).Elem()
+	t.Logf("Device type size: %d, with fields:", typ.Size())
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
+			field.Name,
+			field.Offset,
+			field.Type.Size(),
+			field.Type.Align(),
+		)
+	}
+	checkAlignment(t, "Device.rate.underLoadUntil", unsafe.Offsetof(d.rate)+unsafe.Offsetof(d.rate.underLoadUntil))
+}

device/allowedips.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"container/list"
 	"errors"
 	"math/bits"
 	"net"
@@ -14,15 +15,13 @@ import (
 )
 
 type trieEntry struct {
-	cidr  uint
 	child        [2]*trieEntry
-	bits  net.IP
 	peer         *Peer
-
-	// index of "branching" bit
-
+	bits         net.IP
+	cidr         uint
 	bit_at_byte  uint
 	bit_at_shift uint
+	perPeerElem  *list.Element
 }
 
 func isLittleEndian() bool {
@@ -69,6 +68,17 @@ func commonBits(ip1 net.IP, ip2 net.IP) uint {
 	}
 }
 
+func (node *trieEntry) addToPeerEntries() {
+	node.perPeerElem = node.peer.trieEntries.PushBack(node)
+}
+
+func (node *trieEntry) removeFromPeerEntries() {
+	if node.perPeerElem != nil {
+		node.peer.trieEntries.Remove(node.perPeerElem)
+		node.perPeerElem = nil
+	}
+}
+
 func (node *trieEntry) removeByPeer(p *Peer) *trieEntry {
 	if node == nil {
 		return node
@@ -85,6 +95,7 @@ func (node *trieEntry) removeByPeer(p *Peer) *trieEntry {
 
 	// remove peer & merge
 
+	node.removeFromPeerEntries()
 	node.peer = nil
 	if node.child[0] == nil {
 		return node.child[1]
@@ -96,18 +107,28 @@ func (node *trieEntry) choose(ip net.IP) byte {
 	return (ip[node.bit_at_byte] >> node.bit_at_shift) & 1
 }
 
+func (node *trieEntry) maskSelf() {
+	mask := net.CIDRMask(int(node.cidr), len(node.bits)*8)
+	for i := 0; i < len(mask); i++ {
+		node.bits[i] &= mask[i]
+	}
+}
+
 func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 
 	// at leaf
 
 	if node == nil {
-		return &trieEntry{
+		node := &trieEntry{
 			bits:         ip,
 			peer:         peer,
 			cidr:         cidr,
 			bit_at_byte:  cidr / 8,
 			bit_at_shift: 7 - (cidr % 8),
 		}
+		node.maskSelf()
+		node.addToPeerEntries()
+		return node
 	}
 
 	// traverse deeper
@@ -115,7 +136,9 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 	common := commonBits(node.bits, ip)
 	if node.cidr <= cidr && common >= node.cidr {
 		if node.cidr == cidr {
+			node.removeFromPeerEntries()
 			node.peer = peer
+			node.addToPeerEntries()
 			return node
 		}
 		bit := node.choose(ip)
@@ -132,6 +155,8 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 		bit_at_byte:  cidr / 8,
 		bit_at_shift: 7 - (cidr % 8),
 	}
+	newNode.maskSelf()
+	newNode.addToPeerEntries()
 
 	cidr = min(cidr, common)
 
@@ -146,12 +171,13 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 	// create new parent for node & newNode
 
 	parent := &trieEntry{
-		bits:         ip,
+		bits:         append([]byte{}, ip...),
 		peer:         nil,
 		cidr:         cidr,
 		bit_at_byte:  cidr / 8,
 		bit_at_shift: 7 - (cidr % 8),
 	}
+	parent.maskSelf()
 
 	bit := parent.choose(ip)
 	parent.child[bit] = newNode
@@ -176,44 +202,22 @@ func (node *trieEntry) lookup(ip net.IP) *Peer {
 	return found
 }
 
-func (node *trieEntry) entriesForPeer(p *Peer, results []net.IPNet) []net.IPNet {
-	if node == nil {
-		return results
-	}
-	if node.peer == p {
-		mask := net.CIDRMask(int(node.cidr), len(node.bits)*8)
-		results = append(results, net.IPNet{
-			Mask: mask,
-			IP:   node.bits.Mask(mask),
-		})
-	}
-	results = node.child[0].entriesForPeer(p, results)
-	results = node.child[1].entriesForPeer(p, results)
-	return results
-}
-
 type AllowedIPs struct {
 	IPv4  *trieEntry
 	IPv6  *trieEntry
 	mutex sync.RWMutex
 }
 
-func (table *AllowedIPs) EntriesForPeer(peer *Peer) []net.IPNet {
+func (table *AllowedIPs) EntriesForPeer(peer *Peer, cb func(ip net.IP, cidr uint) bool) {
 	table.mutex.RLock()
 	defer table.mutex.RUnlock()
 
-	allowed := make([]net.IPNet, 0, 10)
-	allowed = table.IPv4.entriesForPeer(peer, allowed)
-	allowed = table.IPv6.entriesForPeer(peer, allowed)
-	return allowed
-}
-
-func (table *AllowedIPs) Reset() {
-	table.mutex.Lock()
-	defer table.mutex.Unlock()
-
-	table.IPv4 = nil
-	table.IPv6 = nil
+	for elem := peer.trieEntries.Front(); elem != nil; elem = elem.Next() {
+		node := elem.Value.(*trieEntry)
+		if !cb(node.bits, node.cidr) {
+			return
+		}
+	}
 }
 
 func (table *AllowedIPs) RemoveByPeer(peer *Peer) {

device/allowedips_rand_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -73,11 +73,11 @@ func TestTrieRandomIPv4(t *testing.T) {
 
 	const AddressLength = 4
 
-	for n := 0; n < NumberOfPeers; n += 1 {
+	for n := 0; n < NumberOfPeers; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < NumberOfAddresses; n += 1 {
+	for n := 0; n < NumberOfAddresses; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -86,7 +86,7 @@ func TestTrieRandomIPv4(t *testing.T) {
 		slow = slow.Insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < NumberOfTests; n += 1 {
+	for n := 0; n < NumberOfTests; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		peer1 := slow.Lookup(addr[:])
@@ -106,11 +106,11 @@ func TestTrieRandomIPv6(t *testing.T) {
 
 	const AddressLength = 16
 
-	for n := 0; n < NumberOfPeers; n += 1 {
+	for n := 0; n < NumberOfPeers; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < NumberOfAddresses; n += 1 {
+	for n := 0; n < NumberOfAddresses; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -119,7 +119,7 @@ func TestTrieRandomIPv6(t *testing.T) {
 		slow = slow.Insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < NumberOfTests; n += 1 {
+	for n := 0; n < NumberOfTests; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		peer1 := slow.Lookup(addr[:])

device/allowedips_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -20,26 +20,6 @@ type testPairCommonBits struct {
 	match uint
 }
 
-type testPairTrieInsert struct {
-	key  []byte
-	cidr uint
-	peer *Peer
-}
-
-type testPairTrieLookup struct {
-	key  []byte
-	peer *Peer
-}
-
-func printTrie(t *testing.T, p *trieEntry) {
-	if p == nil {
-		return
-	}
-	t.Log(p)
-	printTrie(t, p.child[0])
-	printTrie(t, p.child[1])
-}
-
 func TestCommonBits(t *testing.T) {
 
 	tests := []testPairCommonBits{
@@ -70,11 +50,11 @@ func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *test
 
 	const AddressLength = 4
 
-	for n := 0; n < peerNumber; n += 1 {
+	for n := 0; n < peerNumber; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < addressNumber; n += 1 {
+	for n := 0; n < addressNumber; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -82,7 +62,7 @@ func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *test
 		trie = trie.insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < b.N; n += 1 {
+	for n := 0; n < b.N; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		trie.lookup(addr[:])

device/bind_test.go

@@ -1,23 +1,24 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
-import "errors"
+import (
+	"errors"
+
+	"golang.zx2c4.com/wireguard/conn"
+)
 
 type DummyDatagram struct {
 	msg      []byte
-	endpoint Endpoint
-	world    bool // better type
+	endpoint conn.Endpoint
 }
 
 type DummyBind struct {
 	in6    chan DummyDatagram
-	ou6    chan DummyDatagram
 	in4    chan DummyDatagram
-	ou4    chan DummyDatagram
 	closed bool
 }
 
@@ -25,7 +26,7 @@ func (b *DummyBind) SetMark(v uint32) error {
 	return nil
 }
 
-func (b *DummyBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+func (b *DummyBind) ReceiveIPv6(buff []byte) (int, conn.Endpoint, error) {
 	datagram, ok := <-b.in6
 	if !ok {
 		return 0, nil, errors.New("closed")
@@ -34,7 +35,7 @@ func (b *DummyBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	return len(datagram.msg), datagram.endpoint, nil
 }
 
-func (b *DummyBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+func (b *DummyBind) ReceiveIPv4(buff []byte) (int, conn.Endpoint, error) {
 	datagram, ok := <-b.in4
 	if !ok {
 		return 0, nil, errors.New("closed")
@@ -50,6 +51,6 @@ func (b *DummyBind) Close() error {
 	return nil
 }
 
-func (b *DummyBind) Send(buff []byte, end Endpoint) error {
+func (b *DummyBind) Send(buff []byte, end conn.Endpoint) error {
 	return nil
 }

device/boundif_android.go

@@ -1,34 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package device
-
-func (device *Device) PeekLookAtSocketFd4() (fd int, err error) {
-	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
-	if err != nil {
-		return
-	}
-	err = sysconn.Control(func(f uintptr) {
-		fd = int(f)
-	})
-	if err != nil {
-		return
-	}
-	return
-}
-
-func (device *Device) PeekLookAtSocketFd6() (fd int, err error) {
-	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
-	if err != nil {
-		return
-	}
-	err = sysconn.Control(func(f uintptr) {
-		fd = int(f)
-	})
-	if err != nil {
-		return
-	}
-	return
-}

device/boundif_darwin.go

@@ -1,44 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package device
-
-import (
-	"golang.org/x/sys/unix"
-)
-
-func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
-	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
-	if err != nil {
-		return nil
-	}
-	err2 := sysconn.Control(func(fd uintptr) {
-		err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_BOUND_IF, int(interfaceIndex))
-	})
-	if err2 != nil {
-		return err2
-	}
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
-	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
-	if err != nil {
-		return nil
-	}
-	err2 := sysconn.Control(func(fd uintptr) {
-		err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_BOUND_IF, int(interfaceIndex))
-	})
-	if err2 != nil {
-		return err2
-	}
-	if err != nil {
-		return err
-	}
-	return nil
-}

device/channels.go

@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"runtime"
+	"sync"
+)
+
+// An outboundQueue is a channel of QueueOutboundElements awaiting encryption.
+// An outboundQueue is ref-counted using its wg field.
+// An outboundQueue created with newOutboundQueue has one reference.
+// Every additional writer must call wg.Add(1).
+// Every completed writer must call wg.Done().
+// When no further writers will be added,
+// call wg.Done to remove the initial reference.
+// When the refcount hits 0, the queue's channel is closed.
+type outboundQueue struct {
+	c  chan *QueueOutboundElement
+	wg sync.WaitGroup
+}
+
+func newOutboundQueue() *outboundQueue {
+	q := &outboundQueue{
+		c: make(chan *QueueOutboundElement, QueueOutboundSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+// A inboundQueue is similar to an outboundQueue; see those docs.
+type inboundQueue struct {
+	c  chan *QueueInboundElement
+	wg sync.WaitGroup
+}
+
+func newInboundQueue() *inboundQueue {
+	q := &inboundQueue{
+		c: make(chan *QueueInboundElement, QueueInboundSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+// A handshakeQueue is similar to an outboundQueue; see those docs.
+type handshakeQueue struct {
+	c  chan QueueHandshakeElement
+	wg sync.WaitGroup
+}
+
+func newHandshakeQueue() *handshakeQueue {
+	q := &handshakeQueue{
+		c: make(chan QueueHandshakeElement, QueueHandshakeSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+type autodrainingInboundQueue struct {
+	c chan *QueueInboundElement
+}
+
+// newAutodrainingInboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+func newAutodrainingInboundQueue(device *Device) *autodrainingInboundQueue {
+	q := &autodrainingInboundQueue{
+		c: make(chan *QueueInboundElement, QueueInboundSize),
+	}
+	runtime.SetFinalizer(q, device.flushInboundQueue)
+	return q
+}
+
+func (device *Device) flushInboundQueue(q *autodrainingInboundQueue) {
+	for {
+		select {
+		case elem := <-q.c:
+			elem.Lock()
+			device.PutMessageBuffer(elem.buffer)
+			device.PutInboundElement(elem)
+		default:
+			return
+		}
+	}
+}
+
+type autodrainingOutboundQueue struct {
+	c chan *QueueOutboundElement
+}
+
+// newAutodrainingOutboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+// All sends to the channel must be best-effort, because there may be no receivers.
+func newAutodrainingOutboundQueue(device *Device) *autodrainingOutboundQueue {
+	q := &autodrainingOutboundQueue{
+		c: make(chan *QueueOutboundElement, QueueOutboundSize),
+	}
+	runtime.SetFinalizer(q, device.flushOutboundQueue)
+	return q
+}
+
+func (device *Device) flushOutboundQueue(q *autodrainingOutboundQueue) {
+	for {
+		select {
+		case elem := <-q.c:
+			elem.Lock()
+			device.PutMessageBuffer(elem.buffer)
+			device.PutOutboundElement(elem)
+		default:
+			return
+		}
+	}
+}

device/conn.go

@@ -1,187 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package device
-
-import (
-	"errors"
-	"net"
-	"strings"
-
-	"golang.org/x/net/ipv4"
-	"golang.org/x/net/ipv6"
-)
-
-const (
-	ConnRoutineNumber = 2
-)
-
-/* A Bind handles listening on a port for both IPv6 and IPv4 UDP traffic
- */
-type Bind interface {
-	SetMark(value uint32) error
-	ReceiveIPv6(buff []byte) (int, Endpoint, error)
-	ReceiveIPv4(buff []byte) (int, Endpoint, error)
-	Send(buff []byte, end Endpoint) error
-	Close() error
-}
-
-/* An Endpoint maintains the source/destination caching for a peer
- *
- * dst : the remote address of a peer ("endpoint" in uapi terminology)
- * src : the local address from which datagrams originate going to the peer
- */
-type Endpoint interface {
-	ClearSrc()           // clears the source address
-	SrcToString() string // returns the local source address (ip:port)
-	DstToString() string // returns the destination address (ip:port)
-	DstToBytes() []byte  // used for mac2 cookie calculations
-	DstIP() net.IP
-	SrcIP() net.IP
-}
-
-func parseEndpoint(s string) (*net.UDPAddr, error) {
-	// ensure that the host is an IP address
-
-	host, _, err := net.SplitHostPort(s)
-	if err != nil {
-		return nil, err
-	}
-	if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
-		// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
-		// trying to make sure with a small sanity test that this is a real IP address and
-		// not something that's likely to incur DNS lookups.
-		host = host[:i]
-	}
-	if ip := net.ParseIP(host); ip == nil {
-		return nil, errors.New("Failed to parse IP address: " + host)
-	}
-
-	// parse address and port
-
-	addr, err := net.ResolveUDPAddr("udp", s)
-	if err != nil {
-		return nil, err
-	}
-	ip4 := addr.IP.To4()
-	if ip4 != nil {
-		addr.IP = ip4
-	}
-	return addr, err
-}
-
-func unsafeCloseBind(device *Device) error {
-	var err error
-	netc := &device.net
-	if netc.bind != nil {
-		err = netc.bind.Close()
-		netc.bind = nil
-	}
-	netc.stopping.Wait()
-	return err
-}
-
-func (device *Device) BindSetMark(mark uint32) error {
-
-	device.net.Lock()
-	defer device.net.Unlock()
-
-	// check if modified
-
-	if device.net.fwmark == mark {
-		return nil
-	}
-
-	// update fwmark on existing bind
-
-	device.net.fwmark = mark
-	if device.isUp.Get() && device.net.bind != nil {
-		if err := device.net.bind.SetMark(mark); err != nil {
-			return err
-		}
-	}
-
-	// clear cached source addresses
-
-	device.peers.RLock()
-	for _, peer := range device.peers.keyMap {
-		peer.Lock()
-		defer peer.Unlock()
-		if peer.endpoint != nil {
-			peer.endpoint.ClearSrc()
-		}
-	}
-	device.peers.RUnlock()
-
-	return nil
-}
-
-func (device *Device) BindUpdate() error {
-
-	device.net.Lock()
-	defer device.net.Unlock()
-
-	// close existing sockets
-
-	if err := unsafeCloseBind(device); err != nil {
-		return err
-	}
-
-	// open new sockets
-
-	if device.isUp.Get() {
-
-		// bind to new port
-
-		var err error
-		netc := &device.net
-		netc.bind, netc.port, err = CreateBind(netc.port, device)
-		if err != nil {
-			netc.bind = nil
-			netc.port = 0
-			return err
-		}
-
-		// set fwmark
-
-		if netc.fwmark != 0 {
-			err = netc.bind.SetMark(netc.fwmark)
-			if err != nil {
-				return err
-			}
-		}
-
-		// clear cached source addresses
-
-		device.peers.RLock()
-		for _, peer := range device.peers.keyMap {
-			peer.Lock()
-			defer peer.Unlock()
-			if peer.endpoint != nil {
-				peer.endpoint.ClearSrc()
-			}
-		}
-		device.peers.RUnlock()
-
-		// start receiving routines
-
-		device.net.starting.Add(ConnRoutineNumber)
-		device.net.stopping.Add(ConnRoutineNumber)
-		go device.RoutineReceiveIncoming(ipv4.Version, netc.bind)
-		go device.RoutineReceiveIncoming(ipv6.Version, netc.bind)
-		device.net.starting.Wait()
-
-		device.log.Debug.Println("UDP bind has been updated")
-	}
-
-	return nil
-}
-
-func (device *Device) BindClose() error {
-	device.net.Lock()
-	err := unsafeCloseBind(device)
-	device.net.Unlock()
-	return err
-}

device/constants.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -12,8 +12,8 @@ import (
 /* Specification constants */
 
 const (
-	RekeyAfterMessages      = (1 << 64) - (1 << 16) - 1
-	RejectAfterMessages     = (1 << 64) - (1 << 4) - 1
+	RekeyAfterMessages      = (1 << 60)
+	RejectAfterMessages     = (1 << 64) - (1 << 13) - 1
 	RekeyAfterTime          = time.Second * 120
 	RekeyAttemptTime        = time.Second * 90
 	RekeyTimeout            = time.Second * 5
@@ -22,7 +22,7 @@ const (
 	RejectAfterTime         = time.Second * 180
 	KeepaliveTimeout        = time.Second * 10
 	CookieRefreshTime       = time.Second * 120
-	HandshakeInitationRate  = time.Second / 20
+	HandshakeInitationRate  = time.Second / 50
 	PaddingMultiple         = 16
 )
 

device/cookie.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -87,7 +87,7 @@ func (st *CookieChecker) CheckMAC2(msg []byte, src []byte) bool {
 	st.RLock()
 	defer st.RUnlock()
 
-	if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
+	if time.Since(st.mac2.secretSet) > CookieRefreshTime {
 		return false
 	}
 
@@ -124,7 +124,7 @@ func (st *CookieChecker) CreateReply(
 
 	// refresh cookie secret
 
-	if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
+	if time.Since(st.mac2.secretSet) > CookieRefreshTime {
 		st.RUnlock()
 		st.Lock()
 		_, err := rand.Read(st.mac2.secret[:])
@@ -239,7 +239,7 @@ func (st *CookieGenerator) AddMacs(msg []byte) {
 
 	// set mac2
 
-	if time.Now().Sub(st.mac2.cookieSet) > CookieRefreshTime {
+	if time.Since(st.mac2.cookieSet) > CookieRefreshTime {
 		return
 	}
 

device/cookie_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/device.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -11,35 +11,40 @@ import (
 	"sync/atomic"
 	"time"
 
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+
+	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/ratelimiter"
+	"golang.zx2c4.com/wireguard/rwcancel"
 	"golang.zx2c4.com/wireguard/tun"
 )
 
-const (
-	DeviceRoutineNumberPerCPU     = 3
-	DeviceRoutineNumberAdditional = 2
-)
-
 type Device struct {
-	isUp     AtomicBool // device is (going) up
-	isClosed AtomicBool // device is closed? (acting as guard)
-	log      *Logger
-
-	// synchronized resources (locks acquired in order)
-
 	state struct {
-		starting sync.WaitGroup
+		// state holds the device's state. It is accessed atomically.
+		// Use the device.deviceState method to read it.
+		// device.deviceState does not acquire the mutex, so it captures only a snapshot.
+		// During state transitions, the state variable is updated before the device itself.
+		// The state is thus either the current state of the device or
+		// the intended future state of the device.
+		// For example, while executing a call to Up, state will be deviceStateUp.
+		// There is no guarantee that that intended future state of the device
+		// will become the actual state; Up can fail.
+		// The device can also change state multiple times between time of check and time of use.
+		// Unsynchronized uses of state must therefore be advisory/best-effort only.
+		state uint32 // actually a deviceState, but typed uint32 for convenience
+		// stopping blocks until all inputs to Device have been closed.
 		stopping sync.WaitGroup
+		// mu protects state changes.
 		sync.Mutex
-		changing AtomicBool
-		current  bool
 	}
 
 	net struct {
-		starting sync.WaitGroup
 		stopping sync.WaitGroup
 		sync.RWMutex
-		bind   Bind   // bind interface
+		bind          conn.Bind // bind interface
+		netlinkCancel *rwcancel.RWCancel
 		port          uint16 // listening port
 		fwmark        uint32 // mark value (0 = disabled)
 	}
@@ -51,167 +56,191 @@ type Device struct {
 	}
 
 	peers struct {
-		sync.RWMutex
+		empty        AtomicBool // empty reports whether len(keyMap) == 0
+		sync.RWMutex            // protects keyMap
 		keyMap       map[NoisePublicKey]*Peer
 	}
 
-	// unprotected / "self-synchronising resources"
-
 	allowedips    AllowedIPs
 	indexTable    IndexTable
 	cookieChecker CookieChecker
 
 	rate struct {
-		underLoadUntil atomic.Value
+		underLoadUntil int64
 		limiter        ratelimiter.Ratelimiter
 	}
 
 	pool struct {
-		messageBufferPool        *sync.Pool
-		messageBufferReuseChan   chan *[MaxMessageSize]byte
-		inboundElementPool       *sync.Pool
-		inboundElementReuseChan  chan *QueueInboundElement
-		outboundElementPool      *sync.Pool
-		outboundElementReuseChan chan *QueueOutboundElement
+		messageBuffers   *WaitPool
+		inboundElements  *WaitPool
+		outboundElements *WaitPool
 	}
 
 	queue struct {
-		encryption chan *QueueOutboundElement
-		decryption chan *QueueInboundElement
-		handshake  chan QueueHandshakeElement
-	}
-
-	signals struct {
-		stop chan struct{}
+		encryption *outboundQueue
+		decryption *inboundQueue
+		handshake  *handshakeQueue
 	}
 
 	tun struct {
-		device tun.TUNDevice
+		device tun.Device
 		mtu    int32
 	}
+
+	ipcMutex sync.RWMutex
+	closed   chan struct{}
+	log      *Logger
 }
 
-/* Converts the peer into a "zombie", which remains in the peer map,
- * but processes no packets and does not exists in the routing table.
- *
- * Must hold device.peers.Mutex
- */
-func unsafeRemovePeer(device *Device, peer *Peer, key NoisePublicKey) {
+// deviceState represents the state of a Device.
+// There are three states: down, up, closed.
+// Transitions:
+//
+//   down -----+
+//     ↑↓      ↓
+//     up -> closed
+//
+type deviceState uint32
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type deviceState -trimprefix=deviceState
+const (
+	deviceStateDown deviceState = iota
+	deviceStateUp
+	deviceStateClosed
+)
+
+// deviceState returns device.state.state as a deviceState
+// See those docs for how to interpret this value.
+func (device *Device) deviceState() deviceState {
+	return deviceState(atomic.LoadUint32(&device.state.state))
+}
+
+// isClosed reports whether the device is closed (or is closing).
+// See device.state.state comments for how to interpret this value.
+func (device *Device) isClosed() bool {
+	return device.deviceState() == deviceStateClosed
+}
+
+// isUp reports whether the device is up (or is attempting to come up).
+// See device.state.state comments for how to interpret this value.
+func (device *Device) isUp() bool {
+	return device.deviceState() == deviceStateUp
+}
+
+// Must hold device.peers.Lock()
+func removePeerLocked(device *Device, peer *Peer, key NoisePublicKey) {
 	// stop routing and processing of packets
-
 	device.allowedips.RemoveByPeer(peer)
 	peer.Stop()
 
 	// remove from peer map
-
 	delete(device.peers.keyMap, key)
+	device.peers.empty.Set(len(device.peers.keyMap) == 0)
 }
 
-func deviceUpdateState(device *Device) {
-
-	// check if state already being updated (guard)
-
-	if device.state.changing.Swap(true) {
-		return
-	}
-
-	// compare to current state of device
-
+// changeState attempts to change the device state to match want.
+func (device *Device) changeState(want deviceState) (err error) {
 	device.state.Lock()
-
-	newIsUp := device.isUp.Get()
-
-	if newIsUp == device.state.current {
-		device.state.changing.Set(false)
-		device.state.Unlock()
-		return
+	defer device.state.Unlock()
+	old := device.deviceState()
+	if old == deviceStateClosed {
+		// once closed, always closed
+		device.log.Verbosef("Interface closed, ignored requested state %s", want)
+		return nil
 	}
-
-	// change state of device
-
-	switch newIsUp {
-	case true:
-		if err := device.BindUpdate(); err != nil {
-			device.isUp.Set(false)
+	switch want {
+	case old:
+		return nil
+	case deviceStateUp:
+		atomic.StoreUint32(&device.state.state, uint32(deviceStateUp))
+		err = device.upLocked()
+		if err == nil {
 			break
 		}
+		fallthrough // up failed; bring the device all the way back down
+	case deviceStateDown:
+		atomic.StoreUint32(&device.state.state, uint32(deviceStateDown))
+		errDown := device.downLocked()
+		if err == nil {
+			err = errDown
+		}
+	}
+	device.log.Verbosef("Interface state was %s, requested %s, now %s", old, want, device.deviceState())
+	return
+}
+
+// upLocked attempts to bring the device up and reports whether it succeeded.
+// The caller must hold device.state.mu and is responsible for updating device.state.state.
+func (device *Device) upLocked() error {
+	if err := device.BindUpdate(); err != nil {
+		device.log.Errorf("Unable to update bind: %v", err)
+		return err
+	}
+
 	device.peers.RLock()
 	for _, peer := range device.peers.keyMap {
 		peer.Start()
-			if peer.persistentKeepaliveInterval > 0 {
+		if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
 			peer.SendKeepalive()
 		}
 	}
 	device.peers.RUnlock()
+	return nil
+}
+
+// downLocked attempts to bring the device down.
+// The caller must hold device.state.mu and is responsible for updating device.state.state.
+func (device *Device) downLocked() error {
+	err := device.BindClose()
+	if err != nil {
+		device.log.Errorf("Bind close failed: %v", err)
+	}
 
-	case false:
-		device.BindClose()
 	device.peers.RLock()
 	for _, peer := range device.peers.keyMap {
 		peer.Stop()
 	}
 	device.peers.RUnlock()
-	}
-
-	// update state variables
-
-	device.state.current = newIsUp
-	device.state.changing.Set(false)
-	device.state.Unlock()
-
-	// check for state change in the mean time
-
-	deviceUpdateState(device)
+	return err
 }
 
-func (device *Device) Up() {
-
-	// closed device cannot be brought up
-
-	if device.isClosed.Get() {
-		return
-	}
-
-	device.isUp.Set(true)
-	deviceUpdateState(device)
+func (device *Device) Up() error {
+	return device.changeState(deviceStateUp)
 }
 
-func (device *Device) Down() {
-	device.isUp.Set(false)
-	deviceUpdateState(device)
+func (device *Device) Down() error {
+	return device.changeState(deviceStateDown)
 }
 
 func (device *Device) IsUnderLoad() bool {
-
 	// check if currently under load
-
 	now := time.Now()
-	underLoad := len(device.queue.handshake) >= UnderLoadQueueSize
+	underLoad := len(device.queue.handshake.c) >= UnderLoadQueueSize
 	if underLoad {
-		device.rate.underLoadUntil.Store(now.Add(UnderLoadAfterTime))
+		atomic.StoreInt64(&device.rate.underLoadUntil, now.Add(UnderLoadAfterTime).UnixNano())
 		return true
 	}
-
 	// check if recently under load
-
-	until := device.rate.underLoadUntil.Load().(time.Time)
-	return until.After(now)
+	return atomic.LoadInt64(&device.rate.underLoadUntil) > now.UnixNano()
 }
 
 func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
-
 	// lock required resources
 
 	device.staticIdentity.Lock()
 	defer device.staticIdentity.Unlock()
 
+	if sk.Equals(device.staticIdentity.privateKey) {
+		return nil
+	}
+
 	device.peers.Lock()
 	defer device.peers.Unlock()
 
+	lockedPeers := make([]*Peer, 0, len(device.peers.keyMap))
 	for _, peer := range device.peers.keyMap {
 		peer.handshake.mutex.RLock()
-		defer peer.handshake.mutex.RUnlock()
+		lockedPeers = append(lockedPeers, peer)
 	}
 
 	// remove peers with matching public keys
@@ -219,7 +248,9 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 	publicKey := sk.publicKey()
 	for key, peer := range device.peers.keyMap {
 		if peer.handshake.remoteStatic.Equals(publicKey) {
-			unsafeRemovePeer(device, peer, key)
+			peer.handshake.mutex.RUnlock()
+			removePeerLocked(device, peer, key)
+			peer.handshake.mutex.RLock()
 		}
 	}
 
@@ -231,61 +262,45 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 
 	// do static-static DH pre-computations
 
-	rmKey := device.staticIdentity.privateKey.IsZero()
-
-	for key, peer := range device.peers.keyMap {
-
+	expiredPeers := make([]*Peer, 0, len(device.peers.keyMap))
+	for _, peer := range device.peers.keyMap {
 		handshake := &peer.handshake
-
-		if rmKey {
-			handshake.precomputedStaticStatic = [NoisePublicKeySize]byte{}
-		} else {
 		handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(handshake.remoteStatic)
+		expiredPeers = append(expiredPeers, peer)
 	}
 
-		if isZero(handshake.precomputedStaticStatic[:]) {
-			unsafeRemovePeer(device, peer, key)
+	for _, peer := range lockedPeers {
+		peer.handshake.mutex.RUnlock()
 	}
+	for _, peer := range expiredPeers {
+		peer.ExpireCurrentKeypairs()
 	}
 
 	return nil
 }
 
-func NewDevice(tunDevice tun.TUNDevice, logger *Logger) *Device {
+func NewDevice(tunDevice tun.Device, logger *Logger) *Device {
 	device := new(Device)
-
-	device.isUp.Set(false)
-	device.isClosed.Set(false)
-
+	device.state.state = uint32(deviceStateDown)
+	device.closed = make(chan struct{})
 	device.log = logger
-
 	device.tun.device = tunDevice
 	mtu, err := device.tun.device.MTU()
 	if err != nil {
-		logger.Error.Println("Trouble determining MTU, assuming default:", err)
+		device.log.Errorf("Trouble determining MTU, assuming default: %v", err)
 		mtu = DefaultMTU
 	}
 	device.tun.mtu = int32(mtu)
-
 	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
-
 	device.rate.limiter.Init()
-	device.rate.underLoadUntil.Store(time.Time{})
-
 	device.indexTable.Init()
-	device.allowedips.Reset()
-
 	device.PopulatePools()
 
 	// create queues
 
-	device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
-	device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
-	device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
-
-	// prepare signals
-
-	device.signals.stop = make(chan struct{})
+	device.queue.handshake = newHandshakeQueue()
+	device.queue.encryption = newOutboundQueue()
+	device.queue.decryption = newInboundQueue()
 
 	// prepare net
 
@@ -295,21 +310,19 @@ func NewDevice(tunDevice tun.TUNDevice, logger *Logger) *Device {
 	// start workers
 
 	cpus := runtime.NumCPU()
-	device.state.starting.Wait()
 	device.state.stopping.Wait()
-	device.state.stopping.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
-	device.state.starting.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
-	for i := 0; i < cpus; i += 1 {
+	device.queue.encryption.wg.Add(cpus) // One for each RoutineHandshake
+	for i := 0; i < cpus; i++ {
 		go device.RoutineEncryption()
 		go device.RoutineDecryption()
 		go device.RoutineHandshake()
 	}
 
+	device.state.stopping.Add(1)      // RoutineReadFromTUN
+	device.queue.encryption.wg.Add(1) // RoutineReadFromTUN
 	go device.RoutineReadFromTUN()
 	go device.RoutineTUNEventReader()
 
-	device.state.starting.Wait()
-
 	return device
 }
 
@@ -323,12 +336,11 @@ func (device *Device) LookupPeer(pk NoisePublicKey) *Peer {
 func (device *Device) RemovePeer(key NoisePublicKey) {
 	device.peers.Lock()
 	defer device.peers.Unlock()
-
 	// stop peer and remove from routing
 
 	peer, ok := device.peers.keyMap[key]
 	if ok {
-		unsafeRemovePeer(device, peer, key)
+		removePeerLocked(device, peer, key)
 	}
 }
 
@@ -337,61 +349,178 @@ func (device *Device) RemoveAllPeers() {
 	defer device.peers.Unlock()
 
 	for key, peer := range device.peers.keyMap {
-		unsafeRemovePeer(device, peer, key)
+		removePeerLocked(device, peer, key)
 	}
 
 	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
 }
 
-func (device *Device) FlushPacketQueues() {
-	for {
-		select {
-		case elem, ok := <-device.queue.decryption:
-			if ok {
-				elem.Drop()
-			}
-		case elem, ok := <-device.queue.encryption:
-			if ok {
-				elem.Drop()
-			}
-		case <-device.queue.handshake:
-		default:
-			return
-		}
-	}
-
-}
-
 func (device *Device) Close() {
-	if device.isClosed.Swap(true) {
-		return
-	}
-
-	device.state.starting.Wait()
-
-	device.log.Info.Println("Device closing")
-	device.state.changing.Set(true)
 	device.state.Lock()
 	defer device.state.Unlock()
+	if device.isClosed() {
+		return
+	}
+	atomic.StoreUint32(&device.state.state, uint32(deviceStateClosed))
+	device.log.Verbosef("Device closing")
 
 	device.tun.device.Close()
-	device.BindClose()
-
-	device.isUp.Set(false)
-
-	close(device.signals.stop)
+	device.downLocked()
 
+	// Remove peers before closing queues,
+	// because peers assume that queues are active.
 	device.RemoveAllPeers()
 
+	// We kept a reference to the encryption and decryption queues,
+	// in case we started any new peers that might write to them.
+	// No new peers are coming; we are done with these queues.
+	device.queue.encryption.wg.Done()
+	device.queue.decryption.wg.Done()
+	device.queue.handshake.wg.Done()
 	device.state.stopping.Wait()
-	device.FlushPacketQueues()
 
 	device.rate.limiter.Close()
 
-	device.state.changing.Set(false)
-	device.log.Info.Println("Interface closed")
+	device.log.Verbosef("Device closed")
+	close(device.closed)
 }
 
 func (device *Device) Wait() chan struct{} {
-	return device.signals.stop
+	return device.closed
+}
+
+func (device *Device) SendKeepalivesToPeersWithCurrentKeypair() {
+	if !device.isUp() {
+		return
+	}
+
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.keypairs.RLock()
+		sendKeepalive := peer.keypairs.current != nil && !peer.keypairs.current.created.Add(RejectAfterTime).Before(time.Now())
+		peer.keypairs.RUnlock()
+		if sendKeepalive {
+			peer.SendKeepalive()
+		}
+	}
+	device.peers.RUnlock()
+}
+
+func unsafeCloseBind(device *Device) error {
+	var err error
+	netc := &device.net
+	if netc.netlinkCancel != nil {
+		netc.netlinkCancel.Cancel()
+	}
+	if netc.bind != nil {
+		err = netc.bind.Close()
+		netc.bind = nil
+	}
+	netc.stopping.Wait()
+	return err
+}
+
+func (device *Device) Bind() conn.Bind {
+	device.net.Lock()
+	defer device.net.Unlock()
+	return device.net.bind
+}
+
+func (device *Device) BindSetMark(mark uint32) error {
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// check if modified
+	if device.net.fwmark == mark {
+		return nil
+	}
+
+	// update fwmark on existing bind
+	device.net.fwmark = mark
+	if device.isUp() && device.net.bind != nil {
+		if err := device.net.bind.SetMark(mark); err != nil {
+			return err
+		}
+	}
+
+	// clear cached source addresses
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+	}
+	device.peers.RUnlock()
+
+	return nil
+}
+
+func (device *Device) BindUpdate() error {
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// close existing sockets
+	if err := unsafeCloseBind(device); err != nil {
+		return err
+	}
+
+	// open new sockets
+	if !device.isUp() {
+		return nil
+	}
+
+	// bind to new port
+	var err error
+	netc := &device.net
+	netc.bind, netc.port, err = conn.CreateBind(netc.port)
+	if err != nil {
+		netc.bind = nil
+		netc.port = 0
+		return err
+	}
+	netc.netlinkCancel, err = device.startRouteListener(netc.bind)
+	if err != nil {
+		netc.bind.Close()
+		netc.bind = nil
+		netc.port = 0
+		return err
+	}
+
+	// set fwmark
+	if netc.fwmark != 0 {
+		err = netc.bind.SetMark(netc.fwmark)
+		if err != nil {
+			return err
+		}
+	}
+
+	// clear cached source addresses
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+	}
+	device.peers.RUnlock()
+
+	// start receiving routines
+	device.net.stopping.Add(2)
+	device.queue.decryption.wg.Add(2) // each RoutineReceiveIncoming goroutine writes to device.queue.decryption
+	device.queue.handshake.wg.Add(2)  // each RoutineReceiveIncoming goroutine writes to device.queue.handshake
+	go device.RoutineReceiveIncoming(ipv4.Version, netc.bind)
+	go device.RoutineReceiveIncoming(ipv6.Version, netc.bind)
+
+	device.log.Verbosef("UDP bind has been updated")
+	return nil
+}
+
+func (device *Device) BindClose() error {
+	device.net.Lock()
+	err := unsafeCloseBind(device)
+	device.net.Unlock()
+	return err
 }

device/device_test.go

@@ -1,48 +1,434 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
-/* Create two device instances and simulate full WireGuard interaction
- * without network dependencies
- */
+import (
+	"bytes"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"runtime"
+	"runtime/pprof"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"testing"
+	"time"
 
-import "testing"
+	"golang.zx2c4.com/wireguard/tun/tuntest"
+)
 
-func TestDevice(t *testing.T) {
-
-	// prepare tun devices for generating traffic
-
-	tun1, err := CreateDummyTUN("tun1")
-	if err != nil {
-		t.Error("failed to create tun:", err.Error())
+// uapiCfg returns a string that contains cfg formatted use with IpcSet.
+// cfg is a series of alternating key/value strings.
+// uapiCfg exists because editors and humans like to insert
+// whitespace into configs, which can cause failures, some of which are silent.
+// For example, a leading blank newline causes the remainder
+// of the config to be silently ignored.
+func uapiCfg(cfg ...string) string {
+	if len(cfg)%2 != 0 {
+		panic("odd number of args to uapiReader")
 	}
-
-	tun2, err := CreateDummyTUN("tun2")
-	if err != nil {
-		t.Error("failed to create tun:", err.Error())
+	buf := new(bytes.Buffer)
+	for i, s := range cfg {
+		buf.WriteString(s)
+		sep := byte('\n')
+		if i%2 == 0 {
+			sep = '='
 		}
-
-	_ = tun1
-	_ = tun2
-
-	// prepare endpoints
-
-	end1, err := CreateDummyEndpoint()
-	if err != nil {
-		t.Error("failed to create endpoint:", err.Error())
+		buf.WriteByte(sep)
 	}
-
-	end2, err := CreateDummyEndpoint()
-	if err != nil {
-		t.Error("failed to create endpoint:", err.Error())
-	}
-
-	_ = end1
-	_ = end2
-
-	// create binds
-
+	return buf.String()
+}
+
+// genConfigs generates a pair of configs that connect to each other.
+// The configs use distinct, probably-usable ports.
+func genConfigs(tb testing.TB) (cfgs [2]string, endpointCfgs [2]string) {
+	var key1, key2 NoisePrivateKey
+	_, err := rand.Read(key1[:])
+	if err != nil {
+		tb.Errorf("unable to generate private key random bytes: %v", err)
+	}
+	_, err = rand.Read(key2[:])
+	if err != nil {
+		tb.Errorf("unable to generate private key random bytes: %v", err)
+	}
+	pub1, pub2 := key1.publicKey(), key2.publicKey()
+
+	cfgs[0] = uapiCfg(
+		"private_key", hex.EncodeToString(key1[:]),
+		"listen_port", "0",
+		"replace_peers", "true",
+		"public_key", hex.EncodeToString(pub2[:]),
+		"protocol_version", "1",
+		"replace_allowed_ips", "true",
+		"allowed_ip", "1.0.0.2/32",
+	)
+	endpointCfgs[0] = uapiCfg(
+		"public_key", hex.EncodeToString(pub2[:]),
+		"endpoint", "127.0.0.1:%d",
+	)
+	cfgs[1] = uapiCfg(
+		"private_key", hex.EncodeToString(key2[:]),
+		"listen_port", "0",
+		"replace_peers", "true",
+		"public_key", hex.EncodeToString(pub1[:]),
+		"protocol_version", "1",
+		"replace_allowed_ips", "true",
+		"allowed_ip", "1.0.0.1/32",
+	)
+	endpointCfgs[1] = uapiCfg(
+		"public_key", hex.EncodeToString(pub1[:]),
+		"endpoint", "127.0.0.1:%d",
+	)
+	return
+}
+
+// A testPair is a pair of testPeers.
+type testPair [2]testPeer
+
+// A testPeer is a peer used for testing.
+type testPeer struct {
+	tun *tuntest.ChannelTUN
+	dev *Device
+	ip  net.IP
+}
+
+type SendDirection bool
+
+const (
+	Ping SendDirection = true
+	Pong SendDirection = false
+)
+
+func (d SendDirection) String() string {
+	if d == Ping {
+		return "ping"
+	}
+	return "pong"
+}
+
+func (pair *testPair) Send(tb testing.TB, ping SendDirection, done chan struct{}) {
+	tb.Helper()
+	p0, p1 := pair[0], pair[1]
+	if !ping {
+		// pong is the new ping
+		p0, p1 = p1, p0
+	}
+	msg := tuntest.Ping(p0.ip, p1.ip)
+	p1.tun.Outbound <- msg
+	timer := time.NewTimer(5 * time.Second)
+	defer timer.Stop()
+	var err error
+	select {
+	case msgRecv := <-p0.tun.Inbound:
+		if !bytes.Equal(msg, msgRecv) {
+			err = fmt.Errorf("%s did not transit correctly", ping)
+		}
+	case <-timer.C:
+		err = fmt.Errorf("%s did not transit", ping)
+	case <-done:
+	}
+	if err != nil {
+		// The error may have occurred because the test is done.
+		select {
+		case <-done:
+			return
+		default:
+		}
+		// Real error.
+		tb.Error(err)
+	}
+}
+
+// genTestPair creates a testPair.
+func genTestPair(tb testing.TB) (pair testPair) {
+	cfg, endpointCfg := genConfigs(tb)
+	// Bring up a ChannelTun for each config.
+	for i := range pair {
+		p := &pair[i]
+		p.tun = tuntest.NewChannelTUN()
+		p.ip = net.IPv4(1, 0, 0, byte(i+1))
+		level := LogLevelVerbose
+		if _, ok := tb.(*testing.B); ok && !testing.Verbose() {
+			level = LogLevelError
+		}
+		p.dev = NewDevice(p.tun.TUN(), NewLogger(level, fmt.Sprintf("dev%d: ", i)))
+		if err := p.dev.IpcSet(cfg[i]); err != nil {
+			tb.Errorf("failed to configure device %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		if err := p.dev.Up(); err != nil {
+			tb.Errorf("failed to bring up device %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		endpointCfg[i^1] = fmt.Sprintf(endpointCfg[i^1], p.dev.net.port)
+	}
+	for i := range pair {
+		p := &pair[i]
+		if err := p.dev.IpcSet(endpointCfg[i]); err != nil {
+			tb.Errorf("failed to configure device endpoint %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		// The device is ready. Close it when the test completes.
+		tb.Cleanup(p.dev.Close)
+	}
+	return
+}
+
+func TestTwoDevicePing(t *testing.T) {
+	goroutineLeakCheck(t)
+	pair := genTestPair(t)
+	t.Run("ping 1.0.0.1", func(t *testing.T) {
+		pair.Send(t, Ping, nil)
+	})
+	t.Run("ping 1.0.0.2", func(t *testing.T) {
+		pair.Send(t, Pong, nil)
+	})
+}
+
+func TestUpDown(t *testing.T) {
+	goroutineLeakCheck(t)
+	const itrials = 20
+	const otrials = 1
+
+	for n := 0; n < otrials; n++ {
+		pair := genTestPair(t)
+		for i := range pair {
+			for k := range pair[i].dev.peers.keyMap {
+				pair[i].dev.IpcSet(fmt.Sprintf("public_key=%s\npersistent_keepalive_interval=1\n", hex.EncodeToString(k[:])))
+			}
+		}
+		var wg sync.WaitGroup
+		wg.Add(len(pair))
+		for i := range pair {
+			go func(d *Device) {
+				defer wg.Done()
+				for i := 0; i < itrials; i++ {
+					start := time.Now()
+					for {
+						if err := d.Up(); err != nil {
+							if errors.Is(err, syscall.EADDRINUSE) && time.Now().Sub(start) < time.Second*4 {
+								// Some other test process is racing with us, so try again.
+								time.Sleep(time.Millisecond * 10)
+								continue
+							}
+							t.Errorf("failed up bring up device: %v", err)
+						}
+						break
+					}
+					time.Sleep(time.Duration(rand.Intn(int(time.Nanosecond * (0x10000 - 1)))))
+					if err := d.Down(); err != nil {
+						t.Errorf("failed to bring down device: %v", err)
+					}
+					time.Sleep(time.Duration(rand.Intn(int(time.Nanosecond * (0x10000 - 1)))))
+				}
+			}(pair[i].dev)
+		}
+		wg.Wait()
+		for i := range pair {
+			pair[i].dev.Up()
+			pair[i].dev.Close()
+		}
+	}
+}
+
+// TestConcurrencySafety does other things concurrently with tunnel use.
+// It is intended to be used with the race detector to catch data races.
+func TestConcurrencySafety(t *testing.T) {
+	pair := genTestPair(t)
+	done := make(chan struct{})
+
+	const warmupIters = 10
+	var warmup sync.WaitGroup
+	warmup.Add(warmupIters)
+	go func() {
+		// Send data continuously back and forth until we're done.
+		// Note that we may continue to attempt to send data
+		// even after done is closed.
+		i := warmupIters
+		for ping := Ping; ; ping = !ping {
+			pair.Send(t, ping, done)
+			select {
+			case <-done:
+				return
+			default:
+			}
+			if i > 0 {
+				warmup.Done()
+				i--
+			}
+		}
+	}()
+	warmup.Wait()
+
+	applyCfg := func(cfg string) {
+		err := pair[0].dev.IpcSet(cfg)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// Change persistent_keepalive_interval concurrently with tunnel use.
+	t.Run("persistentKeepaliveInterval", func(t *testing.T) {
+		var pub NoisePublicKey
+		for key := range pair[0].dev.peers.keyMap {
+			pub = key
+			break
+		}
+		cfg := uapiCfg(
+			"public_key", hex.EncodeToString(pub[:]),
+			"persistent_keepalive_interval", "1",
+		)
+		for i := 0; i < 1000; i++ {
+			applyCfg(cfg)
+		}
+	})
+
+	// Change private keys concurrently with tunnel use.
+	t.Run("privateKey", func(t *testing.T) {
+		bad := uapiCfg("private_key", "7777777777777777777777777777777777777777777777777777777777777777")
+		good := uapiCfg("private_key", hex.EncodeToString(pair[0].dev.staticIdentity.privateKey[:]))
+		// Set iters to a large number like 1000 to flush out data races quickly.
+		// Don't leave it large. That can cause logical races
+		// in which the handshake is interleaved with key changes
+		// such that the private key appears to be unchanging but
+		// other state gets reset, which can cause handshake failures like
+		// "Received packet with invalid mac1".
+		const iters = 1
+		for i := 0; i < iters; i++ {
+			applyCfg(bad)
+			applyCfg(good)
+		}
+	})
+
+	close(done)
+}
+
+func assertNil(t *testing.T, err error) {
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func assertEqual(t *testing.T, a, b []byte) {
+	if !bytes.Equal(a, b) {
+		t.Fatal(a, "!=", b)
+	}
+}
+
+func randDevice(t *testing.T) *Device {
+	sk, err := newPrivateKey()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tun := newDummyTUN("dummy")
+	logger := NewLogger(LogLevelError, "")
+	device := NewDevice(tun, logger)
+	device.SetPrivateKey(sk)
+	return device
+}
+
+func BenchmarkLatency(b *testing.B) {
+	pair := genTestPair(b)
+
+	// Establish a connection.
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		pair.Send(b, Ping, nil)
+		pair.Send(b, Pong, nil)
+	}
+}
+
+func BenchmarkThroughput(b *testing.B) {
+	pair := genTestPair(b)
+
+	// Establish a connection.
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+
+	// Measure how long it takes to receive b.N packets,
+	// starting when we receive the first packet.
+	var recv uint64
+	var elapsed time.Duration
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		var start time.Time
+		for {
+			<-pair[0].tun.Inbound
+			new := atomic.AddUint64(&recv, 1)
+			if new == 1 {
+				start = time.Now()
+			}
+			// Careful! Don't change this to else if; b.N can be equal to 1.
+			if new == uint64(b.N) {
+				elapsed = time.Since(start)
+				return
+			}
+		}
+	}()
+
+	// Send packets as fast as we can until we've received enough.
+	ping := tuntest.Ping(pair[0].ip, pair[1].ip)
+	pingc := pair[1].tun.Outbound
+	var sent uint64
+	for atomic.LoadUint64(&recv) != uint64(b.N) {
+		sent++
+		pingc <- ping
+	}
+	wg.Wait()
+
+	b.ReportMetric(float64(elapsed)/float64(b.N), "ns/op")
+	b.ReportMetric(1-float64(b.N)/float64(sent), "packet-loss")
+}
+
+func BenchmarkUAPIGet(b *testing.B) {
+	pair := genTestPair(b)
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		pair[0].dev.IpcGetOperation(ioutil.Discard)
+	}
+}
+
+func goroutineLeakCheck(t *testing.T) {
+	goroutines := func() (int, []byte) {
+		p := pprof.Lookup("goroutine")
+		b := new(bytes.Buffer)
+		p.WriteTo(b, 1)
+		return p.Count(), b.Bytes()
+	}
+
+	startGoroutines, startStacks := goroutines()
+	t.Cleanup(func() {
+		if t.Failed() {
+			return
+		}
+		// Give goroutines time to exit, if they need it.
+		for i := 0; i < 10000; i++ {
+			if runtime.NumGoroutine() <= startGoroutines {
+				return
+			}
+			time.Sleep(1 * time.Millisecond)
+		}
+		endGoroutines, endStacks := goroutines()
+		t.Logf("starting stacks:\n%s\n", startStacks)
+		t.Logf("ending stacks:\n%s\n", endStacks)
+		t.Fatalf("expected %d goroutines, got %d, leak?", startGoroutines, endGoroutines)
+	})
 }

device/devicestate_string.go

@@ -0,0 +1,16 @@
+// Code generated by "stringer -type deviceState -trimprefix=deviceState"; DO NOT EDIT.
+
+package device
+
+import "strconv"
+
+const _deviceState_name = "DownUpClosed"
+
+var _deviceState_index = [...]uint8{0, 4, 6, 12}
+
+func (i deviceState) String() string {
+	if i >= deviceState(len(_deviceState_index)-1) {
+		return "deviceState(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _deviceState_name[_deviceState_index[i]:_deviceState_index[i+1]]
+}

device/endpoint_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/indextable.go

@@ -1,14 +1,14 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"crypto/rand"
+	"encoding/binary"
 	"sync"
-	"unsafe"
 )
 
 type IndexTableEntry struct {
@@ -25,7 +25,8 @@ type IndexTable struct {
 func randUint32() (uint32, error) {
 	var integer [4]byte
 	_, err := rand.Read(integer[:])
-	return *(*uint32)(unsafe.Pointer(&integer[0])), err
+	// Arbitrary endianness; both are intrinsified by the Go compiler.
+	return binary.LittleEndian.Uint32(integer[:]), err
 }
 
 func (table *IndexTable) Init() {

device/ip.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/kdf_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/keypair.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,7 +8,9 @@ package device
 import (
 	"crypto/cipher"
 	"sync"
+	"sync/atomic"
 	"time"
+	"unsafe"
 
 	"golang.zx2c4.com/wireguard/replay"
 )
@@ -21,10 +23,10 @@ import (
  */
 
 type Keypair struct {
-	sendNonce    uint64
+	sendNonce    uint64 // accessed atomically
 	send         cipher.AEAD
 	receive      cipher.AEAD
-	replayFilter replay.ReplayFilter
+	replayFilter replay.Filter
 	isInitiator  bool
 	created      time.Time
 	localIndex   uint32
@@ -38,6 +40,14 @@ type Keypairs struct {
 	next     *Keypair
 }
 
+func (kp *Keypairs) storeNext(next *Keypair) {
+	atomic.StorePointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next)), (unsafe.Pointer)(next))
+}
+
+func (kp *Keypairs) loadNext() *Keypair {
+	return (*Keypair)(atomic.LoadPointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next))))
+}
+
 func (kp *Keypairs) Current() *Keypair {
 	kp.RLock()
 	defer kp.RUnlock()

device/logger.go

@@ -1,59 +1,48 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
-	"io"
-	"io/ioutil"
 	"log"
 	"os"
 )
 
+// A Logger provides logging for a Device.
+// The functions are Printf-style functions.
+// They must be safe for concurrent use.
+// They do not require a trailing newline in the format.
+// If nil, that level of logging will be silent.
+type Logger struct {
+	Verbosef func(format string, args ...interface{})
+	Errorf   func(format string, args ...interface{})
+}
+
+// Log levels for use with NewLogger.
 const (
 	LogLevelSilent = iota
 	LogLevelError
-	LogLevelInfo
-	LogLevelDebug
+	LogLevelVerbose
 )
 
-type Logger struct {
-	Debug *log.Logger
-	Info  *log.Logger
-	Error *log.Logger
-}
+// Function for use in Logger for discarding logged lines.
+func DiscardLogf(format string, args ...interface{}) {}
 
+// NewLogger constructs a Logger that writes to stdout.
+// It logs at the specified log level and above.
+// It decorates log lines with the log level, date, time, and prepend.
 func NewLogger(level int, prepend string) *Logger {
-	output := os.Stdout
-	logger := new(Logger)
-
-	logErr, logInfo, logDebug := func() (io.Writer, io.Writer, io.Writer) {
-		if level >= LogLevelDebug {
-			return output, output, output
+	logger := &Logger{DiscardLogf, DiscardLogf}
+	logf := func(prefix string) func(string, ...interface{}) {
+		return log.New(os.Stdout, prefix+": "+prepend, log.Ldate|log.Ltime).Printf
 	}
-		if level >= LogLevelInfo {
-			return output, output, ioutil.Discard
+	if level >= LogLevelVerbose {
+		logger.Verbosef = logf("DEBUG")
 	}
 	if level >= LogLevelError {
-			return output, ioutil.Discard, ioutil.Discard
+		logger.Errorf = logf("ERROR")
 	}
-		return ioutil.Discard, ioutil.Discard, ioutil.Discard
-	}()
-
-	logger.Debug = log.New(logDebug,
-		"DEBUG: "+prepend,
-		log.Ldate|log.Ltime,
-	)
-
-	logger.Info = log.New(logInfo,
-		"INFO: "+prepend,
-		log.Ldate|log.Ltime,
-	)
-	logger.Error = log.New(logErr,
-		"ERROR: "+prepend,
-		log.Ldate|log.Ltime,
-	)
 	return logger
 }

device/misc.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/mobilequirks.go

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+func (device *Device) DisableSomeRoamingForBrokenMobileSemantics() {
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		peer.disableRoaming = peer.endpoint != nil
+	}
+	device.peers.RUnlock()
+}

device/noise-helpers.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -42,7 +42,6 @@ func HMAC2(sum *[blake2s.Size]byte, key, in0, in1 []byte) {
 func KDF1(t0 *[blake2s.Size]byte, key, input []byte) {
 	HMAC1(t0, key, input)
 	HMAC1(t0, t0[:], []byte{0x1})
-	return
 }
 
 func KDF2(t0, t1 *[blake2s.Size]byte, key, input []byte) {
@@ -51,7 +50,6 @@ func KDF2(t0, t1 *[blake2s.Size]byte, key, input []byte) {
 	HMAC1(t0, prk[:], []byte{0x1})
 	HMAC2(t1, prk[:], t0[:], []byte{0x2})
 	setZero(prk[:])
-	return
 }
 
 func KDF3(t0, t1, t2 *[blake2s.Size]byte, key, input []byte) {
@@ -61,7 +59,6 @@ func KDF3(t0, t1, t2 *[blake2s.Size]byte, key, input []byte) {
 	HMAC2(t1, prk[:], t0[:], []byte{0x2})
 	HMAC2(t2, prk[:], t1[:], []byte{0x3})
 	setZero(prk[:])
-	return
 }
 
 func isZero(val []byte) bool {

device/noise-protocol.go

@@ -1,29 +1,51 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"errors"
+	"fmt"
 	"sync"
 	"time"
 
 	"golang.org/x/crypto/blake2s"
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/poly1305"
+
 	"golang.zx2c4.com/wireguard/tai64n"
 )
 
+type handshakeState int
+
+// TODO(crawshaw): add commentary describing each state and the transitions
 const (
-	HandshakeZeroed = iota
-	HandshakeInitiationCreated
-	HandshakeInitiationConsumed
-	HandshakeResponseCreated
-	HandshakeResponseConsumed
+	handshakeZeroed = handshakeState(iota)
+	handshakeInitiationCreated
+	handshakeInitiationConsumed
+	handshakeResponseCreated
+	handshakeResponseConsumed
 )
 
+func (hs handshakeState) String() string {
+	switch hs {
+	case handshakeZeroed:
+		return "handshakeZeroed"
+	case handshakeInitiationCreated:
+		return "handshakeInitiationCreated"
+	case handshakeInitiationConsumed:
+		return "handshakeInitiationConsumed"
+	case handshakeResponseCreated:
+		return "handshakeResponseCreated"
+	case handshakeResponseConsumed:
+		return "handshakeResponseConsumed"
+	default:
+		return fmt.Sprintf("Handshake(UNKNOWN:%d)", int(hs))
+	}
+}
+
 const (
 	NoiseConstruction = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"
 	WGIdentifier      = "WireGuard v1 zx2c4 Jason@zx2c4.com"
@@ -39,13 +61,13 @@ const (
 )
 
 const (
-	MessageInitiationSize      = 148                                           // size of handshake initation message
+	MessageInitiationSize      = 148                                           // size of handshake initiation message
 	MessageResponseSize        = 92                                            // size of response message
 	MessageCookieReplySize     = 64                                            // size of cookie reply message
-	MessageTransportHeaderSize = 16                                            // size of data preceeding content in transport message
+	MessageTransportHeaderSize = 16                                            // size of data preceding content in transport message
 	MessageTransportSize       = MessageTransportHeaderSize + poly1305.TagSize // size of empty transport
 	MessageKeepaliveSize       = MessageTransportSize                          // size of keepalive
-	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake releated message
+	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake related message
 )
 
 const (
@@ -95,11 +117,11 @@ type MessageCookieReply struct {
 }
 
 type Handshake struct {
-	state                     int
+	state                     handshakeState
 	mutex                     sync.RWMutex
 	hash                      [blake2s.Size]byte       // hash value
 	chainKey                  [blake2s.Size]byte       // chain key
-	presharedKey              NoiseSymmetricKey        // psk
+	presharedKey              NoisePresharedKey        // psk
 	localEphemeral            NoisePrivateKey          // ephemeral secret key
 	localIndex                uint32                   // used to clear hash-table
 	remoteIndex               uint32                   // index for sending
@@ -135,7 +157,7 @@ func (h *Handshake) Clear() {
 	setZero(h.chainKey[:])
 	setZero(h.hash[:])
 	h.localIndex = 0
-	h.state = HandshakeZeroed
+	h.state = handshakeZeroed
 }
 
 func (h *Handshake) mixHash(data []byte) {
@@ -154,6 +176,7 @@ func init() {
 }
 
 func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, error) {
+	var errZeroECDHResult = errors.New("ECDH returned all zeros")
 
 	device.staticIdentity.RLock()
 	defer device.staticIdentity.RUnlock()
@@ -162,12 +185,7 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	if isZero(handshake.precomputedStaticStatic[:]) {
-		return nil, errors.New("static shared secret is zero")
-	}
-
 	// create ephemeral key
-
 	var err error
 	handshake.hash = InitialHash
 	handshake.chainKey = InitialChainKey
@@ -176,31 +194,22 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 		return nil, err
 	}
 
-	// assign index
-
-	device.indexTable.Delete(handshake.localIndex)
-	handshake.localIndex, err = device.indexTable.NewIndexForHandshake(peer, handshake)
-
-	if err != nil {
-		return nil, err
-	}
-
 	handshake.mixHash(handshake.remoteStatic[:])
 
 	msg := MessageInitiation{
 		Type:      MessageInitiationType,
 		Ephemeral: handshake.localEphemeral.publicKey(),
-		Sender:    handshake.localIndex,
 	}
 
 	handshake.mixKey(msg.Ephemeral[:])
 	handshake.mixHash(msg.Ephemeral[:])
 
 	// encrypt static key
-
-	func() {
-		var key [chacha20poly1305.KeySize]byte
 	ss := handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
+	if isZero(ss[:]) {
+		return nil, errZeroECDHResult
+	}
+	var key [chacha20poly1305.KeySize]byte
 	KDF2(
 		&handshake.chainKey,
 		&key,
@@ -209,26 +218,32 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 	)
 	aead, _ := chacha20poly1305.New(key[:])
 	aead.Seal(msg.Static[:0], ZeroNonce[:], device.staticIdentity.publicKey[:], handshake.hash[:])
-	}()
 	handshake.mixHash(msg.Static[:])
 
 	// encrypt timestamp
-
-	timestamp := tai64n.Now()
-	func() {
-		var key [chacha20poly1305.KeySize]byte
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		return nil, errZeroECDHResult
+	}
 	KDF2(
 		&handshake.chainKey,
 		&key,
 		handshake.chainKey[:],
 		handshake.precomputedStaticStatic[:],
 	)
-		aead, _ := chacha20poly1305.New(key[:])
+	timestamp := tai64n.Now()
+	aead, _ = chacha20poly1305.New(key[:])
 	aead.Seal(msg.Timestamp[:0], ZeroNonce[:], timestamp[:], handshake.hash[:])
-	}()
+
+	// assign index
+	device.indexTable.Delete(handshake.localIndex)
+	msg.Sender, err = device.indexTable.NewIndexForHandshake(peer, handshake)
+	if err != nil {
+		return nil, err
+	}
+	handshake.localIndex = msg.Sender
 
 	handshake.mixHash(msg.Timestamp[:])
-	handshake.state = HandshakeInitiationCreated
+	handshake.state = handshakeInitiationCreated
 	return &msg, nil
 }
 
@@ -250,16 +265,16 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	mixKey(&chainKey, &InitialChainKey, msg.Ephemeral[:])
 
 	// decrypt static key
-
 	var err error
 	var peerPK NoisePublicKey
-	func() {
 	var key [chacha20poly1305.KeySize]byte
 	ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
+	if isZero(ss[:]) {
+		return nil
+	}
 	KDF2(&chainKey, &key, chainKey[:], ss[:])
 	aead, _ := chacha20poly1305.New(key[:])
 	_, err = aead.Open(peerPK[:0], ZeroNonce[:], msg.Static[:], hash[:])
-	}()
 	if err != nil {
 		return nil
 	}
@@ -273,23 +288,24 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	}
 
 	handshake := &peer.handshake
-	if isZero(handshake.precomputedStaticStatic[:]) {
-		return nil
-	}
 
 	// verify identity
 
 	var timestamp tai64n.Timestamp
-	var key [chacha20poly1305.KeySize]byte
 
 	handshake.mutex.RLock()
+
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		handshake.mutex.RUnlock()
+		return nil
+	}
 	KDF2(
 		&chainKey,
 		&key,
 		chainKey[:],
 		handshake.precomputedStaticStatic[:],
 	)
-	aead, _ := chacha20poly1305.New(key[:])
+	aead, _ = chacha20poly1305.New(key[:])
 	_, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:])
 	if err != nil {
 		handshake.mutex.RUnlock()
@@ -299,11 +315,15 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 
 	// protect against replay & flood
 
-	var ok bool
-	ok = timestamp.After(handshake.lastTimestamp)
-	ok = ok && time.Now().Sub(handshake.lastInitiationConsumption) > HandshakeInitationRate
+	replay := !timestamp.After(handshake.lastTimestamp)
+	flood := time.Since(handshake.lastInitiationConsumption) <= HandshakeInitationRate
 	handshake.mutex.RUnlock()
-	if !ok {
+	if replay {
+		device.log.Verbosef("%v - ConsumeMessageInitiation: handshake replay @ %v", peer, timestamp)
+		return nil
+	}
+	if flood {
+		device.log.Verbosef("%v - ConsumeMessageInitiation: handshake flood", peer)
 		return nil
 	}
 
@@ -315,9 +335,14 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	handshake.chainKey = chainKey
 	handshake.remoteIndex = msg.Sender
 	handshake.remoteEphemeral = msg.Ephemeral
+	if timestamp.After(handshake.lastTimestamp) {
 		handshake.lastTimestamp = timestamp
-	handshake.lastInitiationConsumption = time.Now()
-	handshake.state = HandshakeInitiationConsumed
+	}
+	now := time.Now()
+	if now.After(handshake.lastInitiationConsumption) {
+		handshake.lastInitiationConsumption = now
+	}
+	handshake.state = handshakeInitiationConsumed
 
 	handshake.mutex.Unlock()
 
@@ -332,7 +357,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	if handshake.state != HandshakeInitiationConsumed {
+	if handshake.state != handshakeInitiationConsumed {
 		return nil, errors.New("handshake initiation must be consumed first")
 	}
 
@@ -388,7 +413,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 		handshake.mixHash(msg.Empty[:])
 	}()
 
-	handshake.state = HandshakeResponseCreated
+	handshake.state = handshakeResponseCreated
 
 	return &msg, nil
 }
@@ -418,7 +443,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 		handshake.mutex.RLock()
 		defer handshake.mutex.RUnlock()
 
-		if handshake.state != HandshakeInitiationCreated {
+		if handshake.state != handshakeInitiationCreated {
 			return false
 		}
 
@@ -479,7 +504,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	handshake.hash = hash
 	handshake.chainKey = chainKey
 	handshake.remoteIndex = msg.Sender
-	handshake.state = HandshakeResponseConsumed
+	handshake.state = handshakeResponseConsumed
 
 	handshake.mutex.Unlock()
 
@@ -504,7 +529,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	var sendKey [chacha20poly1305.KeySize]byte
 	var recvKey [chacha20poly1305.KeySize]byte
 
-	if handshake.state == HandshakeResponseConsumed {
+	if handshake.state == handshakeResponseConsumed {
 		KDF2(
 			&sendKey,
 			&recvKey,
@@ -512,7 +537,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 			nil,
 		)
 		isInitiator = true
-	} else if handshake.state == HandshakeResponseCreated {
+	} else if handshake.state == handshakeResponseCreated {
 		KDF2(
 			&recvKey,
 			&sendKey,
@@ -521,7 +546,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 		)
 		isInitiator = false
 	} else {
-		return errors.New("invalid state for keypair derivation")
+		return fmt.Errorf("invalid state for keypair derivation: %v", handshake.state)
 	}
 
 	// zero handshake
@@ -529,7 +554,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	setZero(handshake.chainKey[:])
 	setZero(handshake.hash[:]) // Doesn't necessarily need to be zeroed. Could be used for something interesting down the line.
 	setZero(handshake.localEphemeral[:])
-	peer.handshake.state = HandshakeZeroed
+	peer.handshake.state = handshakeZeroed
 
 	// create AEAD instances
 
@@ -541,8 +566,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	setZero(recvKey[:])
 
 	keypair.created = time.Now()
-	keypair.sendNonce = 0
-	keypair.replayFilter.Init()
+	keypair.replayFilter.Reset()
 	keypair.isInitiator = isInitiator
 	keypair.localIndex = peer.handshake.localIndex
 	keypair.remoteIndex = peer.handshake.remoteIndex
@@ -559,12 +583,12 @@ func (peer *Peer) BeginSymmetricSession() error {
 	defer keypairs.Unlock()
 
 	previous := keypairs.previous
-	next := keypairs.next
+	next := keypairs.loadNext()
 	current := keypairs.current
 
 	if isInitiator {
 		if next != nil {
-			keypairs.next = nil
+			keypairs.storeNext(nil)
 			keypairs.previous = next
 			device.DeleteKeypair(current)
 		} else {
@@ -573,7 +597,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 		device.DeleteKeypair(previous)
 		keypairs.current = keypair
 	} else {
-		keypairs.next = keypair
+		keypairs.storeNext(keypair)
 		device.DeleteKeypair(next)
 		keypairs.previous = nil
 		device.DeleteKeypair(previous)
@@ -584,18 +608,19 @@ func (peer *Peer) BeginSymmetricSession() error {
 
 func (peer *Peer) ReceivedWithKeypair(receivedKeypair *Keypair) bool {
 	keypairs := &peer.keypairs
-	if keypairs.next != receivedKeypair {
+
+	if keypairs.loadNext() != receivedKeypair {
 		return false
 	}
 	keypairs.Lock()
 	defer keypairs.Unlock()
-	if keypairs.next != receivedKeypair {
+	if keypairs.loadNext() != receivedKeypair {
 		return false
 	}
 	old := keypairs.previous
 	keypairs.previous = keypairs.current
 	peer.device.DeleteKeypair(old)
-	keypairs.current = keypairs.next
-	keypairs.next = nil
+	keypairs.current = keypairs.loadNext()
+	keypairs.storeNext(nil)
 	return true
 }

device/noise-types.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -9,19 +9,18 @@ import (
 	"crypto/subtle"
 	"encoding/hex"
 	"errors"
-
-	"golang.org/x/crypto/chacha20poly1305"
 )
 
 const (
 	NoisePublicKeySize    = 32
 	NoisePrivateKeySize   = 32
+	NoisePresharedKeySize = 32
 )
 
 type (
 	NoisePublicKey    [NoisePublicKeySize]byte
 	NoisePrivateKey   [NoisePrivateKeySize]byte
-	NoiseSymmetricKey [chacha20poly1305.KeySize]byte
+	NoisePresharedKey [NoisePresharedKeySize]byte
 	NoiseNonce        uint64 // padded to 12-bytes
 )
 
@@ -52,18 +51,19 @@ func (key *NoisePrivateKey) FromHex(src string) (err error) {
 	return
 }
 
-func (key NoisePrivateKey) ToHex() string {
-	return hex.EncodeToString(key[:])
+func (key *NoisePrivateKey) FromMaybeZeroHex(src string) (err error) {
+	err = loadExactHex(key[:], src)
+	if key.IsZero() {
+		return
+	}
+	key.clamp()
+	return
 }
 
 func (key *NoisePublicKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }
 
-func (key NoisePublicKey) ToHex() string {
-	return hex.EncodeToString(key[:])
-}
-
 func (key NoisePublicKey) IsZero() bool {
 	var zero NoisePublicKey
 	return key.Equals(zero)
@@ -73,10 +73,6 @@ func (key NoisePublicKey) Equals(tar NoisePublicKey) bool {
 	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
 }
 
-func (key *NoiseSymmetricKey) FromHex(src string) error {
+func (key *NoisePresharedKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }
-
-func (key NoiseSymmetricKey) ToHex() string {
-	return hex.EncodeToString(key[:])
-}

device/noise_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -36,8 +36,14 @@ func TestNoiseHandshake(t *testing.T) {
 	defer dev1.Close()
 	defer dev2.Close()
 
-	peer1, _ := dev2.NewPeer(dev1.staticIdentity.privateKey.publicKey())
-	peer2, _ := dev1.NewPeer(dev2.staticIdentity.privateKey.publicKey())
+	peer1, err := dev2.NewPeer(dev1.staticIdentity.privateKey.publicKey())
+	if err != nil {
+		t.Fatal(err)
+	}
+	peer2, err := dev1.NewPeer(dev2.staticIdentity.privateKey.publicKey())
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	assertEqual(
 		t,
@@ -113,7 +119,7 @@ func TestNoiseHandshake(t *testing.T) {
 		t.Fatal("failed to derive keypair for peer 2", err)
 	}
 
-	key1 := peer1.keypairs.next
+	key1 := peer1.keypairs.loadNext()
 	key2 := peer2.keypairs.current
 
 	// encrypting / decryption test

device/peer.go

@@ -1,20 +1,20 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"container/list"
 	"encoding/base64"
 	"errors"
 	"fmt"
 	"sync"
+	"sync/atomic"
 	"time"
-)
 
-const (
-	PeerRoutineNumber = 3
+	"golang.zx2c4.com/wireguard/conn"
 )
 
 type Peer struct {
@@ -23,16 +23,22 @@ type Peer struct {
 	keypairs     Keypairs
 	handshake    Handshake
 	device       *Device
-	endpoint                    Endpoint
-	persistentKeepaliveInterval uint16
+	endpoint     conn.Endpoint
+	stopping     sync.WaitGroup // routines pending stop
 
-	// This must be 64-bit aligned, so make sure the above members come out to even alignment and pad accordingly
+	// These fields are accessed with atomic operations, which must be
+	// 64-bit aligned even on 32-bit platforms. Go guarantees that an
+	// allocated struct will be 64-bit aligned. So we place
+	// atomically-accessed fields up front, so that they can share in
+	// this alignment before smaller fields throw it off.
 	stats struct {
 		txBytes           uint64 // bytes send to peer (endpoint)
 		rxBytes           uint64 // bytes received from peer
 		lastHandshakeNano int64  // nano seconds since epoch
 	}
 
+	disableRoaming bool
+
 	timers struct {
 		retransmitHandshake     *Timer
 		sendKeepalive           *Timer
@@ -44,36 +50,27 @@ type Peer struct {
 		sentLastMinuteHandshake AtomicBool
 	}
 
-	signals struct {
-		newKeypairArrived chan struct{}
-		flushNonceQueue   chan struct{}
+	state struct {
+		sync.Mutex // protects against concurrent Start/Stop
 	}
 
 	queue struct {
-		nonce                           chan *QueueOutboundElement // nonce / pre-handshake queue
-		outbound                        chan *QueueOutboundElement // sequential ordering of work
-		inbound                         chan *QueueInboundElement  // sequential ordering of work
-		packetInNonceQueueIsAwaitingKey AtomicBool
-	}
-
-	routines struct {
-		sync.Mutex                // held when stopping / starting routines
-		starting   sync.WaitGroup // routines pending start
-		stopping   sync.WaitGroup // routines pending stop
-		stop       chan struct{}  // size 0, stop all go routines in peer
+		staged   chan *QueueOutboundElement // staged packets before a handshake is available
+		outbound *autodrainingOutboundQueue // sequential ordering of udp transmission
+		inbound  *autodrainingInboundQueue  // sequential ordering of tun writing
 	}
 
 	cookieGenerator             CookieGenerator
+	trieEntries                 list.List
+	persistentKeepaliveInterval uint32 // accessed atomically
 }
 
 func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
-
-	if device.isClosed.Get() {
+	if device.isClosed() {
 		return nil, errors.New("device closed")
 	}
 
 	// lock resources
-
 	device.staticIdentity.RLock()
 	defer device.staticIdentity.RUnlock()
 
@@ -81,44 +78,44 @@ func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
 	defer device.peers.Unlock()
 
 	// check if over limit
-
 	if len(device.peers.keyMap) >= MaxPeers {
 		return nil, errors.New("too many peers")
 	}
 
 	// create peer
-
 	peer := new(Peer)
 	peer.Lock()
 	defer peer.Unlock()
 
 	peer.cookieGenerator.Init(pk)
 	peer.device = device
-	peer.isRunning.Set(false)
+	peer.queue.outbound = newAutodrainingOutboundQueue(device)
+	peer.queue.inbound = newAutodrainingInboundQueue(device)
+	peer.queue.staged = make(chan *QueueOutboundElement, QueueStagedSize)
 
 	// map public key
-
 	_, ok := device.peers.keyMap[pk]
 	if ok {
 		return nil, errors.New("adding existing peer")
 	}
-	device.peers.keyMap[pk] = peer
 
 	// pre-compute DH
-
 	handshake := &peer.handshake
 	handshake.mutex.Lock()
-	handshake.remoteStatic = pk
 	handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(pk)
+	handshake.remoteStatic = pk
 	handshake.mutex.Unlock()
 
 	// reset endpoint
-
 	peer.endpoint = nil
 
-	// start peer
+	// add
+	device.peers.keyMap[pk] = peer
+	device.peers.empty.Set(false)
 
-	if peer.device.isUp.Get() {
+	// start peer
+	peer.timersInit()
+	if peer.device.isUp() {
 		peer.Start()
 	}
 
@@ -130,6 +127,11 @@ func (peer *Peer) SendBuffer(buffer []byte) error {
 	defer peer.device.net.RUnlock()
 
 	if peer.device.net.bind == nil {
+		// Packets can leak through to SendBuffer while the device is closing.
+		// When that happens, drop them silently to avoid spurious errors.
+		if peer.device.isClosed() {
+			return nil
+		}
 		return errors.New("no bind")
 	}
 
@@ -140,7 +142,11 @@ func (peer *Peer) SendBuffer(buffer []byte) error {
 		return errors.New("no known endpoint for peer")
 	}
 
-	return peer.device.net.bind.Send(buffer, peer.endpoint)
+	err := peer.device.net.bind.Send(buffer, peer.endpoint)
+	if err == nil {
+		atomic.AddUint64(&peer.stats.txBytes, uint64(len(buffer)))
+	}
+	return err
 }
 
 func (peer *Peer) String() string {
@@ -153,51 +159,39 @@ func (peer *Peer) String() string {
 }
 
 func (peer *Peer) Start() {
-
 	// should never start a peer on a closed device
-
-	if peer.device.isClosed.Get() {
+	if peer.device.isClosed() {
 		return
 	}
 
 	// prevent simultaneous start/stop operations
-
-	peer.routines.Lock()
-	defer peer.routines.Unlock()
+	peer.state.Lock()
+	defer peer.state.Unlock()
 
 	if peer.isRunning.Get() {
 		return
 	}
 
 	device := peer.device
-	device.log.Debug.Println(peer, "- Starting...")
+	device.log.Verbosef("%v - Starting...", peer)
 
 	// reset routine state
+	peer.stopping.Wait()
+	peer.stopping.Add(2)
 
-	peer.routines.starting.Wait()
-	peer.routines.stopping.Wait()
-	peer.routines.stop = make(chan struct{})
-	peer.routines.starting.Add(PeerRoutineNumber)
-	peer.routines.stopping.Add(PeerRoutineNumber)
-
-	// prepare queues
-
-	peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
-	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
-	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
-
-	peer.timersInit()
+	peer.handshake.mutex.Lock()
 	peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
-	peer.signals.newKeypairArrived = make(chan struct{}, 1)
-	peer.signals.flushNonceQueue = make(chan struct{}, 1)
+	peer.handshake.mutex.Unlock()
 
-	// wait for routines to start
+	peer.device.queue.encryption.wg.Add(1) // keep encryption queue open for our writes
 
-	go peer.RoutineNonce()
+	peer.timersStart()
+
+	device.flushInboundQueue(peer.queue.inbound)
+	device.flushOutboundQueue(peer.queue.outbound)
 	go peer.RoutineSequentialSender()
 	go peer.RoutineSequentialReceiver()
 
-	peer.routines.starting.Wait()
 	peer.isRunning.Set(true)
 }
 
@@ -210,10 +204,10 @@ func (peer *Peer) ZeroAndFlushAll() {
 	keypairs.Lock()
 	device.DeleteKeypair(keypairs.previous)
 	device.DeleteKeypair(keypairs.current)
-	device.DeleteKeypair(keypairs.next)
+	device.DeleteKeypair(keypairs.loadNext())
 	keypairs.previous = nil
 	keypairs.current = nil
-	keypairs.next = nil
+	keypairs.storeNext(nil)
 	keypairs.Unlock()
 
 	// clear handshake state
@@ -224,44 +218,51 @@ func (peer *Peer) ZeroAndFlushAll() {
 	handshake.Clear()
 	handshake.mutex.Unlock()
 
-	peer.FlushNonceQueue()
+	peer.FlushStagedPackets()
+}
+
+func (peer *Peer) ExpireCurrentKeypairs() {
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	peer.device.indexTable.Delete(handshake.localIndex)
+	handshake.Clear()
+	peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
+	handshake.mutex.Unlock()
+
+	keypairs := &peer.keypairs
+	keypairs.Lock()
+	if keypairs.current != nil {
+		atomic.StoreUint64(&keypairs.current.sendNonce, RejectAfterMessages)
+	}
+	if keypairs.next != nil {
+		next := keypairs.loadNext()
+		atomic.StoreUint64(&next.sendNonce, RejectAfterMessages)
+	}
+	keypairs.Unlock()
 }
 
 func (peer *Peer) Stop() {
-
-	// prevent simultaneous start/stop operations
+	peer.state.Lock()
+	defer peer.state.Unlock()
 
 	if !peer.isRunning.Swap(false) {
 		return
 	}
 
-	peer.routines.starting.Wait()
-
-	peer.routines.Lock()
-	defer peer.routines.Unlock()
-
-	peer.device.log.Debug.Println(peer, "- Stopping...")
+	peer.device.log.Verbosef("%v - Stopping...", peer)
 
 	peer.timersStop()
-
-	// stop & wait for ongoing peer routines
-
-	close(peer.routines.stop)
-	peer.routines.stopping.Wait()
-
-	// close queues
-
-	close(peer.queue.nonce)
-	close(peer.queue.outbound)
-	close(peer.queue.inbound)
+	// Signal that RoutineSequentialSender and RoutineSequentialReceiver should exit.
+	peer.queue.inbound.c <- nil
+	peer.queue.outbound.c <- nil
+	peer.stopping.Wait()
+	peer.device.queue.encryption.wg.Done() // no more writes to encryption queue from us
 
 	peer.ZeroAndFlushAll()
 }
 
-var RoamingDisabled bool
-
-func (peer *Peer) SetEndpointFromPacket(endpoint Endpoint) {
-	if RoamingDisabled {
+func (peer *Peer) SetEndpointFromPacket(endpoint conn.Endpoint) {
+	if peer.disableRoaming {
 		return
 	}
 	peer.Lock()

device/pools.go

@@ -1,89 +1,84 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
-import "sync"
+import (
+	"sync"
+	"sync/atomic"
+)
+
+type WaitPool struct {
+	pool  sync.Pool
+	cond  sync.Cond
+	lock  sync.Mutex
+	count uint32
+	max   uint32
+}
+
+func NewWaitPool(max uint32, new func() interface{}) *WaitPool {
+	p := &WaitPool{pool: sync.Pool{New: new}, max: max}
+	p.cond = sync.Cond{L: &p.lock}
+	return p
+}
+
+func (p *WaitPool) Get() interface{} {
+	if p.max != 0 {
+		p.lock.Lock()
+		for atomic.LoadUint32(&p.count) >= p.max {
+			p.cond.Wait()
+		}
+		atomic.AddUint32(&p.count, 1)
+		p.lock.Unlock()
+	}
+	return p.pool.Get()
+}
+
+func (p *WaitPool) Put(x interface{}) {
+	p.pool.Put(x)
+	if p.max == 0 {
+		return
+	}
+	atomic.AddUint32(&p.count, ^uint32(0))
+	p.cond.Signal()
+}
 
 func (device *Device) PopulatePools() {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.messageBufferPool = &sync.Pool{
-			New: func() interface{} {
+	device.pool.messageBuffers = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new([MaxMessageSize]byte)
-			},
-		}
-		device.pool.inboundElementPool = &sync.Pool{
-			New: func() interface{} {
+	})
+	device.pool.inboundElements = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new(QueueInboundElement)
-			},
-		}
-		device.pool.outboundElementPool = &sync.Pool{
-			New: func() interface{} {
+	})
+	device.pool.outboundElements = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new(QueueOutboundElement)
-			},
-		}
-	} else {
-		device.pool.messageBufferReuseChan = make(chan *[MaxMessageSize]byte, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.messageBufferReuseChan <- new([MaxMessageSize]byte)
-		}
-		device.pool.inboundElementReuseChan = make(chan *QueueInboundElement, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.inboundElementReuseChan <- new(QueueInboundElement)
-		}
-		device.pool.outboundElementReuseChan = make(chan *QueueOutboundElement, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.outboundElementReuseChan <- new(QueueOutboundElement)
-		}
-	}
+	})
 }
 
 func (device *Device) GetMessageBuffer() *[MaxMessageSize]byte {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.messageBufferPool.Get().(*[MaxMessageSize]byte)
-	} else {
-		return <-device.pool.messageBufferReuseChan
-	}
+	return device.pool.messageBuffers.Get().(*[MaxMessageSize]byte)
 }
 
 func (device *Device) PutMessageBuffer(msg *[MaxMessageSize]byte) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.messageBufferPool.Put(msg)
-	} else {
-		device.pool.messageBufferReuseChan <- msg
-	}
+	device.pool.messageBuffers.Put(msg)
 }
 
 func (device *Device) GetInboundElement() *QueueInboundElement {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.inboundElementPool.Get().(*QueueInboundElement)
-	} else {
-		return <-device.pool.inboundElementReuseChan
-	}
+	return device.pool.inboundElements.Get().(*QueueInboundElement)
 }
 
-func (device *Device) PutInboundElement(msg *QueueInboundElement) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.inboundElementPool.Put(msg)
-	} else {
-		device.pool.inboundElementReuseChan <- msg
-	}
+func (device *Device) PutInboundElement(elem *QueueInboundElement) {
+	elem.clearPointers()
+	device.pool.inboundElements.Put(elem)
 }
 
 func (device *Device) GetOutboundElement() *QueueOutboundElement {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.outboundElementPool.Get().(*QueueOutboundElement)
-	} else {
-		return <-device.pool.outboundElementReuseChan
-	}
+	return device.pool.outboundElements.Get().(*QueueOutboundElement)
 }
 
-func (device *Device) PutOutboundElement(msg *QueueOutboundElement) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.outboundElementPool.Put(msg)
-	} else {
-		device.pool.outboundElementReuseChan <- msg
-	}
+func (device *Device) PutOutboundElement(elem *QueueOutboundElement) {
+	elem.clearPointers()
+	device.pool.outboundElements.Put(elem)
 }

device/pools_test.go

@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestWaitPool(t *testing.T) {
+	var wg sync.WaitGroup
+	trials := int32(100000)
+	if raceEnabled {
+		// This test can be very slow with -race.
+		trials /= 10
+	}
+	workers := runtime.NumCPU() + 2
+	if workers-4 <= 0 {
+		t.Skip("Not enough cores")
+	}
+	p := NewWaitPool(uint32(workers-4), func() interface{} { return make([]byte, 16) })
+	wg.Add(workers)
+	max := uint32(0)
+	updateMax := func() {
+		count := atomic.LoadUint32(&p.count)
+		if count > p.max {
+			t.Errorf("count (%d) > max (%d)", count, p.max)
+		}
+		for {
+			old := atomic.LoadUint32(&max)
+			if count <= old {
+				break
+			}
+			if atomic.CompareAndSwapUint32(&max, old, count) {
+				break
+			}
+		}
+	}
+	for i := 0; i < workers; i++ {
+		go func() {
+			defer wg.Done()
+			for atomic.AddInt32(&trials, -1) > 0 {
+				updateMax()
+				x := p.Get()
+				updateMax()
+				time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
+				updateMax()
+				p.Put(x)
+				updateMax()
+			}
+		}()
+	}
+	wg.Wait()
+	if max != p.max {
+		t.Errorf("Actual maximum count (%d) != ideal maximum count (%d)", max, p.max)
+	}
+}
+
+func BenchmarkWaitPool(b *testing.B) {
+	var wg sync.WaitGroup
+	trials := int32(b.N)
+	workers := runtime.NumCPU() + 2
+	if workers-4 <= 0 {
+		b.Skip("Not enough cores")
+	}
+	p := NewWaitPool(uint32(workers-4), func() interface{} { return make([]byte, 16) })
+	wg.Add(workers)
+	b.ResetTimer()
+	for i := 0; i < workers; i++ {
+		go func() {
+			defer wg.Done()
+			for atomic.AddInt32(&trials, -1) > 0 {
+				x := p.Get()
+				time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
+				p.Put(x)
+			}
+		}()
+	}
+	wg.Wait()
+}

device/queueconstants_android.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,6 +8,7 @@ package device
 /* Reduce memory consumption for Android */
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/queueconstants_default.go

@@ -2,12 +2,13 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/queueconstants_ios.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -10,6 +10,7 @@ package device
 /* Fit within memory limits for iOS's Network Extension API, which has stricter requirements */
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/race_disabled_test.go

@@ -0,0 +1,10 @@
+//+build !race
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+const raceEnabled = false

device/race_enabled_test.go

@@ -0,0 +1,10 @@
+//+build race
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+const raceEnabled = true

device/receive.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,8 +8,8 @@ package device
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"net"
-	"strconv"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -17,57 +17,35 @@ import (
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
+
+	"golang.zx2c4.com/wireguard/conn"
 )
 
 type QueueHandshakeElement struct {
 	msgType  uint32
 	packet   []byte
-	endpoint Endpoint
+	endpoint conn.Endpoint
 	buffer   *[MaxMessageSize]byte
 }
 
 type QueueInboundElement struct {
-	dropped int32
 	sync.Mutex
 	buffer   *[MaxMessageSize]byte
 	packet   []byte
 	counter  uint64
 	keypair  *Keypair
-	endpoint Endpoint
+	endpoint conn.Endpoint
 }
 
-func (elem *QueueInboundElement) Drop() {
-	atomic.StoreInt32(&elem.dropped, AtomicTrue)
-}
-
-func (elem *QueueInboundElement) IsDropped() bool {
-	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
-}
-
-func (device *Device) addToInboundAndDecryptionQueues(inboundQueue chan *QueueInboundElement, decryptionQueue chan *QueueInboundElement, element *QueueInboundElement) bool {
-	select {
-	case inboundQueue <- element:
-		select {
-		case decryptionQueue <- element:
-			return true
-		default:
-			element.Drop()
-			element.Unlock()
-			return false
-		}
-	default:
-		device.PutInboundElement(element)
-		return false
-	}
-}
-
-func (device *Device) addToHandshakeQueue(queue chan QueueHandshakeElement, element QueueHandshakeElement) bool {
-	select {
-	case queue <- element:
-		return true
-	default:
-		return false
-	}
+// clearPointers clears elem fields that contain pointers.
+// This makes the garbage collector's life easier and
+// avoids accidentally keeping other objects around unnecessarily.
+// It also reduces the possible collateral damage from use-after-free bugs.
+func (elem *QueueInboundElement) clearPointers() {
+	elem.buffer = nil
+	elem.packet = nil
+	elem.keypair = nil
+	elem.endpoint = nil
 }
 
 /* Called when a new authenticated message has been received
@@ -79,7 +57,7 @@ func (peer *Peer) keepKeyFreshReceiving() {
 		return
 	}
 	keypair := peer.keypairs.Current()
-	if keypair != nil && keypair.isInitiator && time.Now().Sub(keypair.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
+	if keypair != nil && keypair.isInitiator && time.Since(keypair.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
 		peer.timers.sentLastMinuteHandshake.Set(true)
 		peer.SendHandshakeInitiation(false)
 	}
@@ -90,16 +68,15 @@ func (peer *Peer) keepKeyFreshReceiving() {
  * Every time the bind is updated a new routine is started for
  * IPv4 and IPv6 (separately)
  */
-func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
-
-	logDebug := device.log.Debug
+func (device *Device) RoutineReceiveIncoming(IP int, bind conn.Bind) {
 	defer func() {
-		logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - stopped")
+		device.log.Verbosef("Routine: receive incoming IPv%d - stopped", IP)
+		device.queue.decryption.wg.Done()
+		device.queue.handshake.wg.Done()
 		device.net.stopping.Done()
 	}()
 
-	logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - started")
-	device.net.starting.Done()
+	device.log.Verbosef("Routine: receive incoming IPv%d - started", IP)
 
 	// receive datagrams until conn is closed
 
@@ -108,13 +85,11 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 	var (
 		err         error
 		size        int
-		endpoint Endpoint
+		endpoint    conn.Endpoint
+		deathSpiral int
 	)
 
 	for {
-
-		// read next datagram
-
 		switch IP {
 		case ipv4.Version:
 			size, endpoint, err = bind.ReceiveIPv4(buffer[:])
@@ -126,8 +101,18 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 
 		if err != nil {
 			device.PutMessageBuffer(buffer)
+			if errors.Is(err, conn.NetErrClosed) {
 				return
 			}
+			device.log.Errorf("Failed to receive packet: %v", err)
+			if deathSpiral < 10 {
+				deathSpiral++
+				time.Sleep(time.Second / 3)
+				continue
+			}
+			return
+		}
+		deathSpiral = 0
 
 		if size < MinMessageSize {
 			continue
@@ -175,20 +160,19 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 			elem.packet = packet
 			elem.buffer = buffer
 			elem.keypair = keypair
-			elem.dropped = AtomicFalse
 			elem.endpoint = endpoint
 			elem.counter = 0
 			elem.Mutex = sync.Mutex{}
 			elem.Lock()
 
 			// add to decryption queues
-
 			if peer.isRunning.Get() {
-				if device.addToInboundAndDecryptionQueues(peer.queue.inbound, device.queue.decryption, elem) {
+				peer.queue.inbound.c <- elem
+				device.queue.decryption.c <- elem
 				buffer = device.GetMessageBuffer()
+			} else {
+				device.PutInboundElement(elem)
 			}
-			}
-
 			continue
 
 		// otherwise it is a fixed size & handshake related packet
@@ -203,75 +187,40 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 			okay = len(packet) == MessageCookieReplySize
 
 		default:
-			logDebug.Println("Received message with unknown type")
+			device.log.Verbosef("Received message with unknown type")
 		}
 
 		if okay {
-			if (device.addToHandshakeQueue(
-				device.queue.handshake,
-				QueueHandshakeElement{
+			select {
+			case device.queue.handshake.c <- QueueHandshakeElement{
 				msgType:  msgType,
 				buffer:   buffer,
 				packet:   packet,
 				endpoint: endpoint,
-				},
-			)) {
+			}:
 				buffer = device.GetMessageBuffer()
+			default:
 			}
 		}
 	}
 }
 
 func (device *Device) RoutineDecryption() {
-
 	var nonce [chacha20poly1305.NonceSize]byte
 
-	logDebug := device.log.Debug
-	defer func() {
-		logDebug.Println("Routine: decryption worker - stopped")
-		device.state.stopping.Done()
-	}()
-	logDebug.Println("Routine: decryption worker - started")
-	device.state.starting.Done()
-
-	for {
-		select {
-		case <-device.signals.stop:
-			return
-
-		case elem, ok := <-device.queue.decryption:
-
-			if !ok {
-				return
-			}
-
-			// check if dropped
-
-			if elem.IsDropped() {
-				continue
-			}
+	defer device.log.Verbosef("Routine: decryption worker - stopped")
+	device.log.Verbosef("Routine: decryption worker - started")
 
+	for elem := range device.queue.decryption.c {
 		// split message into fields
-
 		counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
 		content := elem.packet[MessageTransportOffsetContent:]
 
-			// expand nonce
-
-			nonce[0x4] = counter[0x0]
-			nonce[0x5] = counter[0x1]
-			nonce[0x6] = counter[0x2]
-			nonce[0x7] = counter[0x3]
-
-			nonce[0x8] = counter[0x4]
-			nonce[0x9] = counter[0x5]
-			nonce[0xa] = counter[0x6]
-			nonce[0xb] = counter[0x7]
-
 		// decrypt and release to consumer
-
 		var err error
 		elem.counter = binary.LittleEndian.Uint64(counter)
+		// copy counter to nonce
+		binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter)
 		elem.packet, err = elem.keypair.receive.Open(
 			content[:0],
 			nonce[:],
@@ -279,51 +228,22 @@ func (device *Device) RoutineDecryption() {
 			nil,
 		)
 		if err != nil {
-				elem.Drop()
-				device.PutMessageBuffer(elem.buffer)
+			elem.packet = nil
 		}
 		elem.Unlock()
 	}
-	}
 }
 
 /* Handles incoming packets related to handshake
  */
 func (device *Device) RoutineHandshake() {
-
-	logInfo := device.log.Info
-	logError := device.log.Error
-	logDebug := device.log.Debug
-
-	var elem QueueHandshakeElement
-	var ok bool
-
 	defer func() {
-		logDebug.Println("Routine: handshake worker - stopped")
-		device.state.stopping.Done()
-		if elem.buffer != nil {
-			device.PutMessageBuffer(elem.buffer)
-		}
+		device.log.Verbosef("Routine: handshake worker - stopped")
+		device.queue.encryption.wg.Done()
 	}()
+	device.log.Verbosef("Routine: handshake worker - started")
 
-	logDebug.Println("Routine: handshake worker - started")
-	device.state.starting.Done()
-
-	for {
-		if elem.buffer != nil {
-			device.PutMessageBuffer(elem.buffer)
-			elem.buffer = nil
-		}
-
-		select {
-		case elem, ok = <-device.queue.handshake:
-		case <-device.signals.stop:
-			return
-		}
-
-		if !ok {
-			return
-		}
+	for elem := range device.queue.handshake.c {
 
 		// handle cookie fields and ratelimiting
 
@@ -337,8 +257,8 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &reply)
 			if err != nil {
-				logDebug.Println("Failed to decode cookie reply")
-				return
+				device.log.Verbosef("Failed to decode cookie reply")
+				goto skip
 			}
 
 			// lookup peer from index
@@ -346,27 +266,27 @@ func (device *Device) RoutineHandshake() {
 			entry := device.indexTable.Lookup(reply.Receiver)
 
 			if entry.peer == nil {
-				continue
+				goto skip
 			}
 
 			// consume reply
 
 			if peer := entry.peer; peer.isRunning.Get() {
-				logDebug.Println("Receiving cookie response from ", elem.endpoint.DstToString())
+				device.log.Verbosef("Receiving cookie response from %s", elem.endpoint.DstToString())
 				if !peer.cookieGenerator.ConsumeReply(&reply) {
-					logDebug.Println("Could not decrypt invalid cookie response")
+					device.log.Verbosef("Could not decrypt invalid cookie response")
 				}
 			}
 
-			continue
+			goto skip
 
 		case MessageInitiationType, MessageResponseType:
 
 			// check mac fields and maybe ratelimit
 
 			if !device.cookieChecker.CheckMAC1(elem.packet) {
-				logDebug.Println("Received packet with invalid mac1")
-				continue
+				device.log.Verbosef("Received packet with invalid mac1")
+				goto skip
 			}
 
 			// endpoints destination address is the source of the datagram
@@ -377,19 +297,19 @@ func (device *Device) RoutineHandshake() {
 
 				if !device.cookieChecker.CheckMAC2(elem.packet, elem.endpoint.DstToBytes()) {
 					device.SendHandshakeCookie(&elem)
-					continue
+					goto skip
 				}
 
 				// check ratelimiter
 
 				if !device.rate.limiter.Allow(elem.endpoint.DstIP()) {
-					continue
+					goto skip
 				}
 			}
 
 		default:
-			logError.Println("Invalid packet ended up in the handshake queue")
-			continue
+			device.log.Errorf("Invalid packet ended up in the handshake queue")
+			goto skip
 		}
 
 		// handle handshake initiation/response content
@@ -403,19 +323,16 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
-				logError.Println("Failed to decode initiation message")
-				continue
+				device.log.Errorf("Failed to decode initiation message")
+				goto skip
 			}
 
 			// consume initiation
 
 			peer := device.ConsumeMessageInitiation(&msg)
 			if peer == nil {
-				logInfo.Println(
-					"Received invalid initiation message from",
-					elem.endpoint.DstToString(),
-				)
-				continue
+				device.log.Verbosef("Received invalid initiation message from %s", elem.endpoint.DstToString())
+				goto skip
 			}
 
 			// update timers
@@ -426,7 +343,8 @@ func (device *Device) RoutineHandshake() {
 			// update endpoint
 			peer.SetEndpointFromPacket(elem.endpoint)
 
-			logDebug.Println(peer, "- Received handshake initiation")
+			device.log.Verbosef("%v - Received handshake initiation", peer)
+			atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
 
 			peer.SendHandshakeResponse()
 
@@ -438,25 +356,23 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
-				logError.Println("Failed to decode response message")
-				continue
+				device.log.Errorf("Failed to decode response message")
+				goto skip
 			}
 
 			// consume response
 
 			peer := device.ConsumeMessageResponse(&msg)
 			if peer == nil {
-				logInfo.Println(
-					"Received invalid response message from",
-					elem.endpoint.DstToString(),
-				)
-				continue
+				device.log.Verbosef("Received invalid response message from %s", elem.endpoint.DstToString())
+				goto skip
 			}
 
 			// update endpoint
 			peer.SetEndpointFromPacket(elem.endpoint)
 
-			logDebug.Println(peer, "- Received handshake response")
+			device.log.Verbosef("%v - Received handshake response", peer)
+			atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
 
 			// update timers
 
@@ -468,201 +384,110 @@ func (device *Device) RoutineHandshake() {
 			err = peer.BeginSymmetricSession()
 
 			if err != nil {
-				logError.Println(peer, "- Failed to derive keypair:", err)
-				continue
+				device.log.Errorf("%v - Failed to derive keypair: %v", peer, err)
+				goto skip
 			}
 
 			peer.timersSessionDerived()
 			peer.timersHandshakeComplete()
 			peer.SendKeepalive()
-			select {
-			case peer.signals.newKeypairArrived <- struct{}{}:
-			default:
-			}
-		}
-	}
-}
-
-func (peer *Peer) elementStopOrFlush(shouldFlush *bool) (stop bool, elemOk bool, elem *QueueInboundElement) {
-	if !*shouldFlush {
-		select {
-		case <-peer.routines.stop:
-			stop = true
-			return
-		case elem, elemOk = <-peer.queue.inbound:
-			return
-		}
-	} else {
-		select {
-		case <-peer.routines.stop:
-			stop = true
-			return
-		case elem, elemOk = <-peer.queue.inbound:
-			return
-		default:
-			*shouldFlush = false
-			err := peer.device.tun.device.Flush()
-			if err != nil {
-				peer.device.log.Error.Printf("Unable to flush packets: %v", err)
-			}
-			return peer.elementStopOrFlush(shouldFlush)
 		}
+	skip:
+		device.PutMessageBuffer(elem.buffer)
 	}
 }
 
 func (peer *Peer) RoutineSequentialReceiver() {
-
 	device := peer.device
-	logInfo := device.log.Info
-	logError := device.log.Error
-	logDebug := device.log.Debug
-
-	var elem *QueueInboundElement
-	var ok bool
-	var stop bool
-
-	shouldFlush := false
-
 	defer func() {
-		logDebug.Println(peer, "- Routine: sequential receiver - stopped")
-		peer.routines.stopping.Done()
-		if elem != nil {
-			if !elem.IsDropped() {
-				device.PutMessageBuffer(elem.buffer)
-			}
-			device.PutInboundElement(elem)
-		}
+		device.log.Verbosef("%v - Routine: sequential receiver - stopped", peer)
+		peer.stopping.Done()
 	}()
+	device.log.Verbosef("%v - Routine: sequential receiver - started", peer)
 
-	logDebug.Println(peer, "- Routine: sequential receiver - started")
-
-	peer.routines.starting.Done()
-
-	for {
-		if elem != nil {
-			if !elem.IsDropped() {
-				device.PutMessageBuffer(elem.buffer)
-			}
-			device.PutInboundElement(elem)
-			elem = nil
-		}
-
-		stop, ok, elem = peer.elementStopOrFlush(&shouldFlush)
-		if stop || !ok {
+	for elem := range peer.queue.inbound.c {
+		if elem == nil {
 			return
 		}
-
-		// wait for decryption
-
+		var err error
 		elem.Lock()
-
-		if elem.IsDropped() {
-			continue
+		if elem.packet == nil {
+			// decryption failed
+			goto skip
 		}
 
-		// check for replay
-
 		if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
-			continue
+			goto skip
 		}
 
-		// update endpoint
 		peer.SetEndpointFromPacket(elem.endpoint)
-
-		// check if using new keypair
 		if peer.ReceivedWithKeypair(elem.keypair) {
 			peer.timersHandshakeComplete()
-			select {
-			case peer.signals.newKeypairArrived <- struct{}{}:
-			default:
-			}
+			peer.SendStagedPackets()
 		}
 
 		peer.keepKeyFreshReceiving()
 		peer.timersAnyAuthenticatedPacketTraversal()
 		peer.timersAnyAuthenticatedPacketReceived()
-
-		// check for keepalive
+		atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)+MinMessageSize))
 
 		if len(elem.packet) == 0 {
-			logDebug.Println(peer, "- Receiving keepalive packet")
-			continue
+			device.log.Verbosef("%v - Receiving keepalive packet", peer)
+			goto skip
 		}
 		peer.timersDataReceived()
 
-		// verify source and strip padding
-
 		switch elem.packet[0] >> 4 {
 		case ipv4.Version:
-
-			// strip padding
-
 			if len(elem.packet) < ipv4.HeaderLen {
-				continue
+				goto skip
 			}
-
 			field := elem.packet[IPv4offsetTotalLength : IPv4offsetTotalLength+2]
 			length := binary.BigEndian.Uint16(field)
 			if int(length) > len(elem.packet) || int(length) < ipv4.HeaderLen {
-				continue
+				goto skip
 			}
-
 			elem.packet = elem.packet[:length]
-
-			// verify IPv4 source
-
 			src := elem.packet[IPv4offsetSrc : IPv4offsetSrc+net.IPv4len]
 			if device.allowedips.LookupIPv4(src) != peer {
-				logInfo.Println(
-					"IPv4 packet with disallowed source address from",
-					peer,
-				)
-				continue
+				device.log.Verbosef("IPv4 packet with disallowed source address from %v", peer)
+				goto skip
 			}
 
 		case ipv6.Version:
-
-			// strip padding
-
 			if len(elem.packet) < ipv6.HeaderLen {
-				continue
+				goto skip
 			}
-
 			field := elem.packet[IPv6offsetPayloadLength : IPv6offsetPayloadLength+2]
 			length := binary.BigEndian.Uint16(field)
 			length += ipv6.HeaderLen
 			if int(length) > len(elem.packet) {
-				continue
+				goto skip
 			}
-
 			elem.packet = elem.packet[:length]
-
-			// verify IPv6 source
-
 			src := elem.packet[IPv6offsetSrc : IPv6offsetSrc+net.IPv6len]
 			if device.allowedips.LookupIPv6(src) != peer {
-				logInfo.Println(
-					peer,
-					"sent packet with disallowed IPv6 source",
-				)
-				continue
+				device.log.Verbosef("IPv6 packet with disallowed source address from %v", peer)
+				goto skip
 			}
 
 		default:
-			logInfo.Println("Packet with invalid IP version from", peer)
-			continue
+			device.log.Verbosef("Packet with invalid IP version from %v", peer)
+			goto skip
 		}
 
-		// write to tun device
-
-		offset := MessageTransportOffsetContent
-		atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
-		_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)
-		if err == nil {
-			shouldFlush = true
+		_, err = device.tun.device.Write(elem.buffer[:MessageTransportOffsetContent+len(elem.packet)], MessageTransportOffsetContent)
+		if err != nil && !device.isClosed() {
+			device.log.Errorf("Failed to write packet to TUN device: %v", err)
 		}
-		if err != nil && !device.isClosed.Get() {
-			logError.Println("Failed to write packet to TUN device:", err)
+		if len(peer.queue.inbound.c) == 0 {
+			err = device.tun.device.Flush()
+			if err != nil {
+				peer.device.log.Errorf("Unable to flush packets: %v", err)
 			}
 		}
+	skip:
+		device.PutMessageBuffer(elem.buffer)
+		device.PutInboundElement(elem)
+	}
 }

device/send.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -43,7 +43,6 @@ import (
  */
 
 type QueueOutboundElement struct {
-	dropped int32
 	sync.Mutex
 	buffer  *[MaxMessageSize]byte // slice holding the packet data
 	packet  []byte                // slice of "buffer" (always!)
@@ -54,73 +53,38 @@ type QueueOutboundElement struct {
 
 func (device *Device) NewOutboundElement() *QueueOutboundElement {
 	elem := device.GetOutboundElement()
-	elem.dropped = AtomicFalse
 	elem.buffer = device.GetMessageBuffer()
 	elem.Mutex = sync.Mutex{}
 	elem.nonce = 0
-	elem.keypair = nil
-	elem.peer = nil
+	// keypair and peer were cleared (if necessary) by clearPointers.
 	return elem
 }
 
-func (elem *QueueOutboundElement) Drop() {
-	atomic.StoreInt32(&elem.dropped, AtomicTrue)
-}
-
-func (elem *QueueOutboundElement) IsDropped() bool {
-	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
-}
-
-func addToNonceQueue(queue chan *QueueOutboundElement, element *QueueOutboundElement, device *Device) {
-	for {
-		select {
-		case queue <- element:
-			return
-		default:
-			select {
-			case old := <-queue:
-				device.PutMessageBuffer(old.buffer)
-				device.PutOutboundElement(old)
-			default:
-			}
-		}
-	}
-}
-
-func addToOutboundAndEncryptionQueues(outboundQueue chan *QueueOutboundElement, encryptionQueue chan *QueueOutboundElement, element *QueueOutboundElement) {
-	select {
-	case outboundQueue <- element:
-		select {
-		case encryptionQueue <- element:
-			return
-		default:
-			element.Drop()
-			element.peer.device.PutMessageBuffer(element.buffer)
-			element.Unlock()
-		}
-	default:
-		element.peer.device.PutMessageBuffer(element.buffer)
-		element.peer.device.PutOutboundElement(element)
-	}
+// clearPointers clears elem fields that contain pointers.
+// This makes the garbage collector's life easier and
+// avoids accidentally keeping other objects around unnecessarily.
+// It also reduces the possible collateral damage from use-after-free bugs.
+func (elem *QueueOutboundElement) clearPointers() {
+	elem.buffer = nil
+	elem.packet = nil
+	elem.keypair = nil
+	elem.peer = nil
 }
 
 /* Queues a keepalive if no packets are queued for peer
  */
-func (peer *Peer) SendKeepalive() bool {
-	if len(peer.queue.nonce) != 0 || peer.queue.packetInNonceQueueIsAwaitingKey.Get() || !peer.isRunning.Get() {
-		return false
-	}
+func (peer *Peer) SendKeepalive() {
+	if len(peer.queue.staged) == 0 && peer.isRunning.Get() {
 		elem := peer.device.NewOutboundElement()
-	elem.packet = nil
 		select {
-	case peer.queue.nonce <- elem:
-		peer.device.log.Debug.Println(peer, "- Sending keepalive packet")
-		return true
+		case peer.queue.staged <- elem:
+			peer.device.log.Verbosef("%v - Sending keepalive packet", peer)
 		default:
 			peer.device.PutMessageBuffer(elem.buffer)
 			peer.device.PutOutboundElement(elem)
-		return false
 		}
+	}
+	peer.SendStagedPackets()
 }
 
 func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
@@ -129,25 +93,25 @@ func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
 	}
 
 	peer.handshake.mutex.RLock()
-	if time.Now().Sub(peer.handshake.lastSentHandshake) < RekeyTimeout {
+	if time.Since(peer.handshake.lastSentHandshake) < RekeyTimeout {
 		peer.handshake.mutex.RUnlock()
 		return nil
 	}
 	peer.handshake.mutex.RUnlock()
 
 	peer.handshake.mutex.Lock()
-	if time.Now().Sub(peer.handshake.lastSentHandshake) < RekeyTimeout {
+	if time.Since(peer.handshake.lastSentHandshake) < RekeyTimeout {
 		peer.handshake.mutex.Unlock()
 		return nil
 	}
 	peer.handshake.lastSentHandshake = time.Now()
 	peer.handshake.mutex.Unlock()
 
-	peer.device.log.Debug.Println(peer, "- Sending handshake initiation")
+	peer.device.log.Verbosef("%v - Sending handshake initiation", peer)
 
 	msg, err := peer.device.CreateMessageInitiation(peer)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to create initiation message:", err)
+		peer.device.log.Errorf("%v - Failed to create initiation message: %v", peer, err)
 		return err
 	}
 
@@ -162,7 +126,7 @@ func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
 
 	err = peer.SendBuffer(packet)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to send handshake initiation", err)
+		peer.device.log.Errorf("%v - Failed to send handshake initiation: %v", peer, err)
 	}
 	peer.timersHandshakeInitiated()
 
@@ -174,11 +138,11 @@ func (peer *Peer) SendHandshakeResponse() error {
 	peer.handshake.lastSentHandshake = time.Now()
 	peer.handshake.mutex.Unlock()
 
-	peer.device.log.Debug.Println(peer, "- Sending handshake response")
+	peer.device.log.Verbosef("%v - Sending handshake response", peer)
 
 	response, err := peer.device.CreateMessageResponse(peer)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to create response message:", err)
+		peer.device.log.Errorf("%v - Failed to create response message: %v", peer, err)
 		return err
 	}
 
@@ -190,7 +154,7 @@ func (peer *Peer) SendHandshakeResponse() error {
 
 	err = peer.BeginSymmetricSession()
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to derive keypair:", err)
+		peer.device.log.Errorf("%v - Failed to derive keypair: %v", peer, err)
 		return err
 	}
 
@@ -200,19 +164,18 @@ func (peer *Peer) SendHandshakeResponse() error {
 
 	err = peer.SendBuffer(packet)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to send handshake response", err)
+		peer.device.log.Errorf("%v - Failed to send handshake response: %v", peer, err)
 	}
 	return err
 }
 
 func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement) error {
-
-	device.log.Debug.Println("Sending cookie response for denied handshake message for", initiatingElem.endpoint.DstToString())
+	device.log.Verbosef("Sending cookie response for denied handshake message for %v", initiatingElem.endpoint.DstToString())
 
 	sender := binary.LittleEndian.Uint32(initiatingElem.packet[4:8])
 	reply, err := device.cookieChecker.CreateReply(initiatingElem.packet, sender, initiatingElem.endpoint.DstToBytes())
 	if err != nil {
-		device.log.Error.Println("Failed to create cookie reply:", err)
+		device.log.Errorf("Failed to create cookie reply: %v", err)
 		return err
 	}
 
@@ -220,10 +183,7 @@ func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement)
 	writer := bytes.NewBuffer(buff[:0])
 	binary.Write(writer, binary.LittleEndian, reply)
 	device.net.bind.Send(writer.Bytes(), initiatingElem.endpoint)
-	if err != nil {
-		device.log.Error.Println("Failed to send cookie reply:", err)
-	}
-	return err
+	return nil
 }
 
 func (peer *Peer) keepKeyFreshSending() {
@@ -232,28 +192,24 @@ func (peer *Peer) keepKeyFreshSending() {
 		return
 	}
 	nonce := atomic.LoadUint64(&keypair.sendNonce)
-	if nonce > RekeyAfterMessages || (keypair.isInitiator && time.Now().Sub(keypair.created) > RekeyAfterTime) {
+	if nonce > RekeyAfterMessages || (keypair.isInitiator && time.Since(keypair.created) > RekeyAfterTime) {
 		peer.SendHandshakeInitiation(false)
 	}
 }
 
 /* Reads packets from the TUN and inserts
- * into nonce queue for peer
+ * into staged queue for peer
  *
  * Obs. Single instance per TUN device
  */
 func (device *Device) RoutineReadFromTUN() {
-
-	logDebug := device.log.Debug
-	logError := device.log.Error
-
 	defer func() {
-		logDebug.Println("Routine: TUN reader - stopped")
+		device.log.Verbosef("Routine: TUN reader - stopped")
 		device.state.stopping.Done()
+		device.queue.encryption.wg.Done()
 	}()
 
-	logDebug.Println("Routine: TUN reader - started")
-	device.state.starting.Done()
+	device.log.Verbosef("Routine: TUN reader - started")
 
 	var elem *QueueOutboundElement
 
@@ -270,8 +226,8 @@ func (device *Device) RoutineReadFromTUN() {
 		size, err := device.tun.device.Read(elem.buffer[:], offset)
 
 		if err != nil {
-			if !device.isClosed.Get() {
-				logError.Println("Failed to read packet from TUN device:", err)
+			if !device.isClosed() {
+				device.log.Errorf("Failed to read packet from TUN device: %v", err)
 				device.Close()
 			}
 			device.PutMessageBuffer(elem.buffer)
@@ -304,207 +260,117 @@ func (device *Device) RoutineReadFromTUN() {
 			peer = device.allowedips.LookupIPv6(dst)
 
 		default:
-			logDebug.Println("Received packet with unknown IP version")
+			device.log.Verbosef("Received packet with unknown IP version")
 		}
 
 		if peer == nil {
 			continue
 		}
-
-		// insert into nonce/pre-handshake queue
-
 		if peer.isRunning.Get() {
-			if peer.queue.packetInNonceQueueIsAwaitingKey.Get() {
-				peer.SendHandshakeInitiation(false)
-			}
-			addToNonceQueue(peer.queue.nonce, elem, device)
+			peer.StagePacket(elem)
 			elem = nil
+			peer.SendStagedPackets()
 		}
 	}
 }
 
-func (peer *Peer) FlushNonceQueue() {
+func (peer *Peer) StagePacket(elem *QueueOutboundElement) {
+	for {
 		select {
-	case peer.signals.flushNonceQueue <- struct{}{}:
+		case peer.queue.staged <- elem:
+			return
 		default:
 		}
+		select {
+		case tooOld := <-peer.queue.staged:
+			peer.device.PutMessageBuffer(tooOld.buffer)
+			peer.device.PutOutboundElement(tooOld)
+		default:
+		}
+	}
 }
 
-/* Queues packets when there is no handshake.
- * Then assigns nonces to packets sequentially
- * and creates "work" structs for workers
- *
- * Obs. A single instance per peer
- */
-func (peer *Peer) RoutineNonce() {
-	var keypair *Keypair
-
-	device := peer.device
-	logDebug := device.log.Debug
-
-	flush := func() {
-		for {
-			select {
-			case elem := <-peer.queue.nonce:
-				device.PutMessageBuffer(elem.buffer)
-				device.PutOutboundElement(elem)
-			default:
-				return
-			}
-		}
-	}
-
-	defer func() {
-		flush()
-		logDebug.Println(peer, "- Routine: nonce worker - stopped")
-		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-		peer.routines.stopping.Done()
-	}()
-
-	peer.routines.starting.Done()
-	logDebug.Println(peer, "- Routine: nonce worker - started")
-
-	for {
-	NextPacket:
-		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-
-		select {
-		case <-peer.routines.stop:
-			return
-
-		case <-peer.signals.flushNonceQueue:
-			flush()
-			goto NextPacket
-
-		case elem, ok := <-peer.queue.nonce:
-
-			if !ok {
+func (peer *Peer) SendStagedPackets() {
+top:
+	if len(peer.queue.staged) == 0 || !peer.device.isUp() {
 		return
 	}
 
-			// make sure to always pick the newest key
-
-			for {
-
-				// check validity of newest key pair
-
-				keypair = peer.keypairs.Current()
-				if keypair != nil && keypair.sendNonce < RejectAfterMessages {
-					if time.Now().Sub(keypair.created) < RejectAfterTime {
-						break
-					}
-				}
-				peer.queue.packetInNonceQueueIsAwaitingKey.Set(true)
-
-				// no suitable key pair, request for new handshake
-
-				select {
-				case <-peer.signals.newKeypairArrived:
-				default:
-				}
-
+	keypair := peer.keypairs.Current()
+	if keypair == nil || atomic.LoadUint64(&keypair.sendNonce) >= RejectAfterMessages || time.Since(keypair.created) >= RejectAfterTime {
 		peer.SendHandshakeInitiation(false)
-
-				// wait for key to be established
-
-				logDebug.Println(peer, "- Awaiting keypair")
-
-				select {
-				case <-peer.signals.newKeypairArrived:
-					logDebug.Println(peer, "- Obtained awaited keypair")
-
-				case <-peer.signals.flushNonceQueue:
-					device.PutMessageBuffer(elem.buffer)
-					device.PutOutboundElement(elem)
-					flush()
-					goto NextPacket
-
-				case <-peer.routines.stop:
-					device.PutMessageBuffer(elem.buffer)
-					device.PutOutboundElement(elem)
 		return
 	}
-			}
-			peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-
-			// populate work element
 
+	for {
+		select {
+		case elem := <-peer.queue.staged:
 			elem.peer = peer
 			elem.nonce = atomic.AddUint64(&keypair.sendNonce, 1) - 1
-
-			// double check in case of race condition added by future code
-
 			if elem.nonce >= RejectAfterMessages {
 				atomic.StoreUint64(&keypair.sendNonce, RejectAfterMessages)
-				device.PutMessageBuffer(elem.buffer)
-				device.PutOutboundElement(elem)
-				goto NextPacket
+				peer.StagePacket(elem) // XXX: Out of order, but we can't front-load go chans
+				goto top
 			}
 
 			elem.keypair = keypair
-			elem.dropped = AtomicFalse
 			elem.Lock()
 
 			// add to parallel and sequential queue
-			addToOutboundAndEncryptionQueues(peer.queue.outbound, device.queue.encryption, elem)
+			if peer.isRunning.Get() {
+				peer.queue.outbound.c <- elem
+				peer.device.queue.encryption.c <- elem
+			} else {
+				peer.device.PutMessageBuffer(elem.buffer)
+				peer.device.PutOutboundElement(elem)
+			}
+		default:
+			return
 		}
 	}
 }
 
+func (peer *Peer) FlushStagedPackets() {
+	for {
+		select {
+		case elem := <-peer.queue.staged:
+			peer.device.PutMessageBuffer(elem.buffer)
+			peer.device.PutOutboundElement(elem)
+		default:
+			return
+		}
+	}
+}
+
+func calculatePaddingSize(packetSize, mtu int) int {
+	lastUnit := packetSize
+	if mtu == 0 {
+		return ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)) - lastUnit
+	}
+	if lastUnit > mtu {
+		lastUnit %= mtu
+	}
+	paddedSize := ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1))
+	if paddedSize > mtu {
+		paddedSize = mtu
+	}
+	return paddedSize - lastUnit
+}
+
 /* Encrypts the elements in the queue
  * and marks them for sequential consumption (by releasing the mutex)
  *
  * Obs. One instance per core
  */
 func (device *Device) RoutineEncryption() {
-
+	var paddingZeros [PaddingMultiple]byte
 	var nonce [chacha20poly1305.NonceSize]byte
 
-	logDebug := device.log.Debug
-
-	defer func() {
-		for {
-			select {
-			case elem, ok := <-device.queue.encryption:
-				if ok && !elem.IsDropped() {
-					elem.Drop()
-					device.PutMessageBuffer(elem.buffer)
-					elem.Unlock()
-				}
-			default:
-				goto out
-			}
-		}
-	out:
-		logDebug.Println("Routine: encryption worker - stopped")
-		device.state.stopping.Done()
-	}()
-
-	logDebug.Println("Routine: encryption worker - started")
-	device.state.starting.Done()
-
-	for {
-
-		// fetch next element
-
-		select {
-		case <-device.signals.stop:
-			return
-
-		case elem, ok := <-device.queue.encryption:
-
-			if !ok {
-				return
-			}
-
-			// check if dropped
-
-			if elem.IsDropped() {
-				continue
-			}
+	defer device.log.Verbosef("Routine: encryption worker - stopped")
+	device.log.Verbosef("Routine: encryption worker - started")
 
+	for elem := range device.queue.encryption.c {
 		// populate header fields
-
 		header := elem.buffer[:MessageTransportHeaderSize]
 
 		fieldType := header[0:4]
@@ -516,16 +382,8 @@ func (device *Device) RoutineEncryption() {
 		binary.LittleEndian.PutUint64(fieldNonce, elem.nonce)
 
 		// pad content to multiple of 16
-
-			mtu := int(atomic.LoadInt32(&device.tun.mtu))
-			lastUnit := len(elem.packet) % mtu
-			paddedSize := (lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)
-			if paddedSize > mtu {
-				paddedSize = mtu
-			}
-			for i := len(elem.packet); i < paddedSize; i++ {
-				elem.packet = append(elem.packet, 0)
-			}
+		paddingSize := calculatePaddingSize(len(elem.packet), int(atomic.LoadInt32(&device.tun.mtu)))
+		elem.packet = append(elem.packet, paddingZeros[:paddingSize]...)
 
 		// encrypt content and release to consumer
 
@@ -538,7 +396,6 @@ func (device *Device) RoutineEncryption() {
 		)
 		elem.Unlock()
 	}
-	}
 }
 
 /* Sequentially reads packets from queue and sends to endpoint
@@ -547,50 +404,26 @@ func (device *Device) RoutineEncryption() {
  * The routine terminates then the outbound queue is closed.
  */
 func (peer *Peer) RoutineSequentialSender() {
-
 	device := peer.device
-
-	logDebug := device.log.Debug
-	logError := device.log.Error
-
 	defer func() {
-		for {
-			select {
-			case elem, ok := <-peer.queue.outbound:
-				if ok {
-					if !elem.IsDropped() {
-						device.PutMessageBuffer(elem.buffer)
-						elem.Drop()
-					}
-					device.PutOutboundElement(elem)
-				}
-			default:
-				goto out
-			}
-		}
-	out:
-		logDebug.Println(peer, "- Routine: sequential sender - stopped")
-		peer.routines.stopping.Done()
+		defer device.log.Verbosef("%v - Routine: sequential sender - stopped", peer)
+		peer.stopping.Done()
 	}()
+	device.log.Verbosef("%v - Routine: sequential sender - started", peer)
 
-	logDebug.Println(peer, "- Routine: sequential sender - started")
-
-	peer.routines.starting.Done()
-
-	for {
-		select {
-
-		case <-peer.routines.stop:
-			return
-
-		case elem, ok := <-peer.queue.outbound:
-
-			if !ok {
+	for elem := range peer.queue.outbound.c {
+		if elem == nil {
 			return
 		}
-
 		elem.Lock()
-			if elem.IsDropped() {
+		if !peer.isRunning.Get() {
+			// peer has been stopped; return re-usable elems to the shared pool.
+			// This is an optimization only. It is possible for the peer to be stopped
+			// immediately after this check, in which case, elem will get processed.
+			// The timers and SendBuffer code are resilient to a few stragglers.
+			// TODO(josharian): rework peer shutdown order to ensure
+			// that we never accidentally keep timers alive longer than necessary.
+			device.PutMessageBuffer(elem.buffer)
 			device.PutOutboundElement(elem)
 			continue
 		}
@@ -600,7 +433,6 @@ func (peer *Peer) RoutineSequentialSender() {
 
 		// send message and return buffer to pool
 
-			length := uint64(len(elem.packet))
 		err := peer.SendBuffer(elem.packet)
 		if len(elem.packet) != MessageKeepaliveSize {
 			peer.timersDataSent()
@@ -608,12 +440,10 @@ func (peer *Peer) RoutineSequentialSender() {
 		device.PutMessageBuffer(elem.buffer)
 		device.PutOutboundElement(elem)
 		if err != nil {
-				logError.Println(peer, "- Failed to send data packet", err)
+			device.log.Errorf("%v - Failed to send data packet: %v", peer, err)
 			continue
 		}
-			atomic.AddUint64(&peer.stats.txBytes, length)
 
 		peer.keepKeyFreshSending()
 	}
-	}
 }

device/sticky_default.go

@@ -0,0 +1,12 @@
+// +build !linux android
+
+package device
+
+import (
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/rwcancel"
+)
+
+func (device *Device) startRouteListener(bind conn.Bind) (*rwcancel.RWCancel, error) {
+	return nil, nil
+}

device/sticky_linux.go

@@ -0,0 +1,218 @@
+// +build !android
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ *
+ * This implements userspace semantics of "sticky sockets", modeled after
+ * WireGuard's kernelspace implementation. This is more or less a straight port
+ * of the sticky-sockets.c example code:
+ * https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
+ *
+ * Currently there is no way to achieve this within the net package:
+ * See e.g. https://github.com/golang/go/issues/17930
+ * So this code is remains platform dependent.
+ */
+
+package device
+
+import (
+	"sync"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/rwcancel"
+)
+
+func (device *Device) startRouteListener(bind conn.Bind) (*rwcancel.RWCancel, error) {
+	netlinkSock, err := createNetlinkRouteSocket()
+	if err != nil {
+		return nil, err
+	}
+	netlinkCancel, err := rwcancel.NewRWCancel(netlinkSock)
+	if err != nil {
+		unix.Close(netlinkSock)
+		return nil, err
+	}
+
+	go device.routineRouteListener(bind, netlinkSock, netlinkCancel)
+
+	return netlinkCancel, nil
+}
+
+func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netlinkCancel *rwcancel.RWCancel) {
+	type peerEndpointPtr struct {
+		peer     *Peer
+		endpoint *conn.Endpoint
+	}
+	var reqPeer map[uint32]peerEndpointPtr
+	var reqPeerLock sync.Mutex
+
+	defer netlinkCancel.Close()
+	defer unix.Close(netlinkSock)
+
+	for msg := make([]byte, 1<<16); ; {
+		var err error
+		var msgn int
+		for {
+			msgn, _, _, _, err = unix.Recvmsg(netlinkSock, msg[:], nil, 0)
+			if err == nil || !rwcancel.RetryAfterError(err) {
+				break
+			}
+			if !netlinkCancel.ReadyRead() {
+				return
+			}
+		}
+		if err != nil {
+			return
+		}
+
+		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
+
+			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
+
+			if uint(hdr.Len) > uint(len(remain)) {
+				break
+			}
+
+			switch hdr.Type {
+			case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
+				if hdr.Seq <= MaxPeers && hdr.Seq > 0 {
+					if uint(len(remain)) < uint(hdr.Len) {
+						break
+					}
+					if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
+						attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
+						for {
+							if uint(len(attr)) < uint(unix.SizeofRtAttr) {
+								break
+							}
+							attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
+							if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
+								break
+							}
+							if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
+								ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
+								reqPeerLock.Lock()
+								if reqPeer == nil {
+									reqPeerLock.Unlock()
+									break
+								}
+								pePtr, ok := reqPeer[hdr.Seq]
+								reqPeerLock.Unlock()
+								if !ok {
+									break
+								}
+								pePtr.peer.Lock()
+								if &pePtr.peer.endpoint != pePtr.endpoint {
+									pePtr.peer.Unlock()
+									break
+								}
+								if uint32(pePtr.peer.endpoint.(*conn.NativeEndpoint).Src4().Ifindex) == ifidx {
+									pePtr.peer.Unlock()
+									break
+								}
+								pePtr.peer.endpoint.(*conn.NativeEndpoint).ClearSrc()
+								pePtr.peer.Unlock()
+							}
+							attr = attr[attrhdr.Len:]
+						}
+					}
+					break
+				}
+				reqPeerLock.Lock()
+				reqPeer = make(map[uint32]peerEndpointPtr)
+				reqPeerLock.Unlock()
+				go func() {
+					device.peers.RLock()
+					i := uint32(1)
+					for _, peer := range device.peers.keyMap {
+						peer.RLock()
+						if peer.endpoint == nil {
+							peer.RUnlock()
+							continue
+						}
+						nativeEP, _ := peer.endpoint.(*conn.NativeEndpoint)
+						if nativeEP == nil {
+							peer.RUnlock()
+							continue
+						}
+						if nativeEP.IsV6() || nativeEP.Src4().Ifindex == 0 {
+							peer.RUnlock()
+							break
+						}
+						nlmsg := struct {
+							hdr     unix.NlMsghdr
+							msg     unix.RtMsg
+							dsthdr  unix.RtAttr
+							dst     [4]byte
+							srchdr  unix.RtAttr
+							src     [4]byte
+							markhdr unix.RtAttr
+							mark    uint32
+						}{
+							unix.NlMsghdr{
+								Type:  uint16(unix.RTM_GETROUTE),
+								Flags: unix.NLM_F_REQUEST,
+								Seq:   i,
+							},
+							unix.RtMsg{
+								Family:  unix.AF_INET,
+								Dst_len: 32,
+								Src_len: 32,
+							},
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_DST,
+							},
+							nativeEP.Dst4().Addr,
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_SRC,
+							},
+							nativeEP.Src4().Src,
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_MARK,
+							},
+							uint32(bind.LastMark()),
+						}
+						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
+						reqPeerLock.Lock()
+						reqPeer[i] = peerEndpointPtr{
+							peer:     peer,
+							endpoint: &peer.endpoint,
+						}
+						reqPeerLock.Unlock()
+						peer.RUnlock()
+						i++
+						_, err := netlinkCancel.Write((*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
+						if err != nil {
+							break
+						}
+					}
+					device.peers.RUnlock()
+				}()
+			}
+			remain = remain[hdr.Len:]
+		}
+	}
+}
+
+func createNetlinkRouteSocket() (int, error) {
+	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
+	if err != nil {
+		return -1, err
+	}
+	saddr := &unix.SockaddrNetlink{
+		Family: unix.AF_NETLINK,
+		Groups: unix.RTMGRP_IPV4_ROUTE,
+	}
+	err = unix.Bind(sock, saddr)
+	if err != nil {
+		unix.Close(sock)
+		return -1, err
+	}
+	return sock, nil
+}

device/timers.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  *
  * This is based heavily on timers.c from the kernel implementation.
  */
@@ -14,10 +14,8 @@ import (
 	"time"
 )
 
-/* This Timer structure and related functions should roughly copy the interface of
- * the Linux kernel's struct timer_list.
- */
-
+// A Timer manages time-based aspects of the WireGuard protocol.
+// Timer roughly copies the interface of the Linux kernel's struct timer_list.
 type Timer struct {
 	*time.Timer
 	modifyingLock sync.RWMutex
@@ -29,18 +27,17 @@ func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
 	timer := &Timer{}
 	timer.Timer = time.AfterFunc(time.Hour, func() {
 		timer.runningLock.Lock()
+		defer timer.runningLock.Unlock()
 
 		timer.modifyingLock.Lock()
 		if !timer.isPending {
 			timer.modifyingLock.Unlock()
-			timer.runningLock.Unlock()
 			return
 		}
 		timer.isPending = false
 		timer.modifyingLock.Unlock()
 
 		expirationFunction(peer)
-		timer.runningLock.Unlock()
 	})
 	timer.Stop()
 	return timer
@@ -74,12 +71,12 @@ func (timer *Timer) IsPending() bool {
 }
 
 func (peer *Peer) timersActive() bool {
-	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp.Get() && len(peer.device.peers.keyMap) > 0
+	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp() && !peer.device.peers.empty.Get()
 }
 
 func expiredRetransmitHandshake(peer *Peer) {
 	if atomic.LoadUint32(&peer.timers.handshakeAttempts) > MaxTimerHandshakes {
-		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d attempts, giving up\n", peer, MaxTimerHandshakes+2)
+		peer.device.log.Verbosef("%s - Handshake did not complete after %d attempts, giving up", peer, MaxTimerHandshakes+2)
 
 		if peer.timersActive() {
 			peer.timers.sendKeepalive.Del()
@@ -88,7 +85,7 @@ func expiredRetransmitHandshake(peer *Peer) {
 		/* We drop all packets without a keypair and don't try again,
 		 * if we try unsuccessfully for too long to make a handshake.
 		 */
-		peer.FlushNonceQueue()
+		peer.FlushStagedPackets()
 
 		/* We set a timer for destroying any residue that might be left
 		 * of a partial exchange.
@@ -98,7 +95,7 @@ func expiredRetransmitHandshake(peer *Peer) {
 		}
 	} else {
 		atomic.AddUint32(&peer.timers.handshakeAttempts, 1)
-		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d seconds, retrying (try %d)\n", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
+		peer.device.log.Verbosef("%s - Handshake did not complete after %d seconds, retrying (try %d)", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
 
 		/* We clear the endpoint address src address, in case this is the cause of trouble. */
 		peer.Lock()
@@ -122,7 +119,7 @@ func expiredSendKeepalive(peer *Peer) {
 }
 
 func expiredNewHandshake(peer *Peer) {
-	peer.device.log.Debug.Printf("%s - Retrying handshake because we stopped hearing back after %d seconds\n", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
+	peer.device.log.Verbosef("%s - Retrying handshake because we stopped hearing back after %d seconds", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
 	/* We clear the endpoint address src address, in case this is the cause of trouble. */
 	peer.Lock()
 	if peer.endpoint != nil {
@@ -134,12 +131,12 @@ func expiredNewHandshake(peer *Peer) {
 }
 
 func expiredZeroKeyMaterial(peer *Peer) {
-	peer.device.log.Debug.Printf("%s - Removing all keys, since we haven't received a new one in %d seconds\n", peer, int((RejectAfterTime * 3).Seconds()))
+	peer.device.log.Verbosef("%s - Removing all keys, since we haven't received a new one in %d seconds", peer, int((RejectAfterTime * 3).Seconds()))
 	peer.ZeroAndFlushAll()
 }
 
 func expiredPersistentKeepalive(peer *Peer) {
-	if peer.persistentKeepaliveInterval > 0 {
+	if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
 		peer.SendKeepalive()
 	}
 }
@@ -147,7 +144,7 @@ func expiredPersistentKeepalive(peer *Peer) {
 /* Should be called after an authenticated data packet is sent. */
 func (peer *Peer) timersDataSent() {
 	if peer.timersActive() && !peer.timers.newHandshake.IsPending() {
-		peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout)
+		peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
 	}
 }
 
@@ -202,8 +199,9 @@ func (peer *Peer) timersSessionDerived() {
 
 /* Should be called before a packet with authentication -- keepalive, data, or handshake -- is sent, or after one is received. */
 func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
-	if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
-		peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
+	keepalive := atomic.LoadUint32(&peer.persistentKeepaliveInterval)
+	if keepalive > 0 && peer.timersActive() {
+		peer.timers.persistentKeepalive.Mod(time.Duration(keepalive) * time.Second)
 	}
 }
 
@@ -213,6 +211,9 @@ func (peer *Peer) timersInit() {
 	peer.timers.newHandshake = peer.NewTimer(expiredNewHandshake)
 	peer.timers.zeroKeyMaterial = peer.NewTimer(expiredZeroKeyMaterial)
 	peer.timers.persistentKeepalive = peer.NewTimer(expiredPersistentKeepalive)
+}
+
+func (peer *Peer) timersStart() {
 	atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
 	peer.timers.sentLastMinuteHandshake.Set(false)
 	peer.timers.needAnotherKeepalive.Set(false)

device/tun.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"fmt"
 	"sync/atomic"
 
 	"golang.zx2c4.com/wireguard/tun"
@@ -14,43 +15,40 @@ import (
 const DefaultMTU = 1420
 
 func (device *Device) RoutineTUNEventReader() {
-	setUp := false
-	logDebug := device.log.Debug
-	logInfo := device.log.Info
-	logError := device.log.Error
-
-	logDebug.Println("Routine: event worker - started")
-	device.state.starting.Done()
+	device.log.Verbosef("Routine: event worker - started")
 
 	for event := range device.tun.device.Events() {
-		if event&tun.TUNEventMTUUpdate != 0 {
+		if event&tun.EventMTUUpdate != 0 {
 			mtu, err := device.tun.device.MTU()
-			old := atomic.LoadInt32(&device.tun.mtu)
 			if err != nil {
-				logError.Println("Failed to load updated MTU of device:", err)
-			} else if int(old) != mtu {
-				if mtu+MessageTransportSize > MaxMessageSize {
-					logInfo.Println("MTU updated:", mtu, "(too large)")
-				} else {
-					logInfo.Println("MTU updated:", mtu)
+				device.log.Errorf("Failed to load updated MTU of device: %v", err)
+				continue
 			}
-				atomic.StoreInt32(&device.tun.mtu, int32(mtu))
+			if mtu < 0 {
+				device.log.Errorf("MTU not updated to negative value: %v", mtu)
+				continue
+			}
+			var tooLarge string
+			if mtu > MaxContentSize {
+				tooLarge = fmt.Sprintf(" (too large, capped at %v)", MaxContentSize)
+				mtu = MaxContentSize
+			}
+			old := atomic.SwapInt32(&device.tun.mtu, int32(mtu))
+			if int(old) != mtu {
+				device.log.Verbosef("MTU updated: %v%s", mtu, tooLarge)
 			}
 		}
 
-		if event&tun.TUNEventUp != 0 && !setUp {
-			logInfo.Println("Interface set up")
-			setUp = true
+		if event&tun.EventUp != 0 {
+			device.log.Verbosef("Interface up requested")
 			device.Up()
 		}
 
-		if event&tun.TUNEventDown != 0 && setUp {
-			logInfo.Println("Interface set down")
-			setUp = false
+		if event&tun.EventDown != 0 {
+			device.log.Verbosef("Interface down requested")
 			device.Down()
 		}
 	}
 
-	logDebug.Println("Routine: event worker - stopped")
-	device.state.stopping.Done()
+	device.log.Verbosef("Routine: event worker - stopped")
 }

device/tun_test.go

@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"errors"
+	"os"
+
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+// newDummyTUN creates a dummy TUN device with the specified name.
+func newDummyTUN(name string) tun.Device {
+	return &dummyTUN{
+		name:    name,
+		packets: make(chan []byte, 100),
+		events:  make(chan tun.Event, 10),
+	}
+}
+
+// A dummyTUN is a tun.Device which is used in unit tests.
+type dummyTUN struct {
+	name    string
+	mtu     int
+	packets chan []byte
+	events  chan tun.Event
+}
+
+func (d *dummyTUN) Events() chan tun.Event { return d.events }
+func (*dummyTUN) File() *os.File           { return nil }
+func (*dummyTUN) Flush() error             { return nil }
+func (d *dummyTUN) MTU() (int, error)      { return d.mtu, nil }
+func (d *dummyTUN) Name() (string, error)  { return d.name, nil }
+
+func (d *dummyTUN) Close() error {
+	close(d.events)
+	close(d.packets)
+	return nil
+}
+
+func (d *dummyTUN) Read(b []byte, offset int) (int, error) {
+	buf, ok := <-d.packets
+	if !ok {
+		return 0, errors.New("device closed")
+	}
+	copy(b[offset:], buf)
+	return len(buf), nil
+}
+
+func (d *dummyTUN) Write(b []byte, offset int) (int, error) {
+	d.packets <- b[offset:]
+	return len(b), nil
+}

device/uapi.go

@@ -1,39 +1,75 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"bufio"
+	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"net"
 	"strconv"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"time"
 
+	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/ipc"
 )
 
 type IPCError struct {
-	int64
+	code int64 // error code
+	err  error // underlying/wrapped error
 }
 
 func (s IPCError) Error() string {
-	return fmt.Sprintf("IPC error: %d", s.int64)
+	return fmt.Sprintf("IPC error %d: %v", s.code, s.err)
+}
+
+func (s IPCError) Unwrap() error {
+	return s.err
 }
 
 func (s IPCError) ErrorCode() int64 {
-	return s.int64
+	return s.code
 }
 
-func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
-	lines := make([]string, 0, 100)
-	send := func(line string) {
-		lines = append(lines, line)
+func ipcErrorf(code int64, msg string, args ...interface{}) *IPCError {
+	return &IPCError{code: code, err: fmt.Errorf(msg, args...)}
+}
+
+var byteBufferPool = &sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
+// IpcGetOperation implements the WireGuard configuration protocol "get" operation.
+// See https://www.wireguard.com/xplatform/#configuration-protocol for details.
+func (device *Device) IpcGetOperation(w io.Writer) error {
+	device.ipcMutex.RLock()
+	defer device.ipcMutex.RUnlock()
+
+	buf := byteBufferPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer byteBufferPool.Put(buf)
+	sendf := func(format string, args ...interface{}) {
+		fmt.Fprintf(buf, format, args...)
+		buf.WriteByte('\n')
+	}
+	keyf := func(prefix string, key *[32]byte) {
+		buf.Grow(len(key)*2 + 2 + len(prefix))
+		buf.WriteString(prefix)
+		buf.WriteByte('=')
+		const hex = "0123456789abcdef"
+		for i := 0; i < len(key); i++ {
+			buf.WriteByte(hex[key[i]>>4])
+			buf.WriteByte(hex[key[i]&0xf])
+		}
+		buf.WriteByte('\n')
 	}
 
 	func() {
@@ -52,15 +88,15 @@ func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
 		// serialize device related values
 
 		if !device.staticIdentity.privateKey.IsZero() {
-			send("private_key=" + device.staticIdentity.privateKey.ToHex())
+			keyf("private_key", (*[32]byte)(&device.staticIdentity.privateKey))
 		}
 
 		if device.net.port != 0 {
-			send(fmt.Sprintf("listen_port=%d", device.net.port))
+			sendf("listen_port=%d", device.net.port)
 		}
 
 		if device.net.fwmark != 0 {
-			send(fmt.Sprintf("fwmark=%d", device.net.fwmark))
+			sendf("fwmark=%d", device.net.fwmark)
 		}
 
 		// serialize each peer state
@@ -69,315 +105,308 @@ func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
 			peer.RLock()
 			defer peer.RUnlock()
 
-			send("public_key=" + peer.handshake.remoteStatic.ToHex())
-			send("preshared_key=" + peer.handshake.presharedKey.ToHex())
-			send("protocol_version=1")
+			keyf("public_key", (*[32]byte)(&peer.handshake.remoteStatic))
+			keyf("preshared_key", (*[32]byte)(&peer.handshake.presharedKey))
+			sendf("protocol_version=1")
 			if peer.endpoint != nil {
-				send("endpoint=" + peer.endpoint.DstToString())
+				sendf("endpoint=%s", peer.endpoint.DstToString())
 			}
 
 			nano := atomic.LoadInt64(&peer.stats.lastHandshakeNano)
 			secs := nano / time.Second.Nanoseconds()
 			nano %= time.Second.Nanoseconds()
 
-			send(fmt.Sprintf("last_handshake_time_sec=%d", secs))
-			send(fmt.Sprintf("last_handshake_time_nsec=%d", nano))
-			send(fmt.Sprintf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes)))
-			send(fmt.Sprintf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes)))
-			send(fmt.Sprintf("persistent_keepalive_interval=%d", peer.persistentKeepaliveInterval))
-
-			for _, ip := range device.allowedips.EntriesForPeer(peer) {
-				send("allowed_ip=" + ip.String())
-			}
+			sendf("last_handshake_time_sec=%d", secs)
+			sendf("last_handshake_time_nsec=%d", nano)
+			sendf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes))
+			sendf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes))
+			sendf("persistent_keepalive_interval=%d", atomic.LoadUint32(&peer.persistentKeepaliveInterval))
 
+			device.allowedips.EntriesForPeer(peer, func(ip net.IP, cidr uint) bool {
+				sendf("allowed_ip=%s/%d", ip.String(), cidr)
+				return true
+			})
 		}
 	}()
 
 	// send lines (does not require resource locks)
-
-	for _, line := range lines {
-		_, err := socket.WriteString(line + "\n")
-		if err != nil {
-			return &IPCError{ipc.IpcErrorIO}
-		}
+	if _, err := w.Write(buf.Bytes()); err != nil {
+		return ipcErrorf(ipc.IpcErrorIO, "failed to write output: %w", err)
 	}
 
 	return nil
 }
 
-func (device *Device) IpcSetOperation(socket *bufio.Reader) *IPCError {
-	scanner := bufio.NewScanner(socket)
-	logError := device.log.Error
-	logDebug := device.log.Debug
+// IpcSetOperation implements the WireGuard configuration protocol "set" operation.
+// See https://www.wireguard.com/xplatform/#configuration-protocol for details.
+func (device *Device) IpcSetOperation(r io.Reader) (err error) {
+	device.ipcMutex.Lock()
+	defer device.ipcMutex.Unlock()
 
-	var peer *Peer
+	defer func() {
+		if err != nil {
+			device.log.Errorf("%v", err)
+		}
+	}()
 
-	dummy := false
+	peer := new(ipcSetPeer)
 	deviceConfig := true
 
+	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
-
-		// parse line
-
 		line := scanner.Text()
 		if line == "" {
+			// Blank line means terminate operation.
 			return nil
 		}
 		parts := strings.Split(line, "=")
 		if len(parts) != 2 {
-			return &IPCError{ipc.IpcErrorProtocol}
+			return ipcErrorf(ipc.IpcErrorProtocol, "failed to parse line %q, found %d =-separated parts, want 2", line, len(parts))
 		}
 		key := parts[0]
 		value := parts[1]
 
-		/* device configuration */
-
+		if key == "public_key" {
 			if deviceConfig {
+				deviceConfig = false
+			}
+			peer.handlePostConfig()
+			// Load/create the peer we are now configuring.
+			err := device.handlePublicKeyLine(peer, value)
+			if err != nil {
+				return err
+			}
+			continue
+		}
 
+		var err error
+		if deviceConfig {
+			err = device.handleDeviceLine(key, value)
+		} else {
+			err = device.handlePeerLine(peer, key, value)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	peer.handlePostConfig()
+
+	if err := scanner.Err(); err != nil {
+		return ipcErrorf(ipc.IpcErrorIO, "failed to read input: %w", err)
+	}
+	return nil
+}
+
+func (device *Device) handleDeviceLine(key, value string) error {
 	switch key {
 	case "private_key":
 		var sk NoisePrivateKey
-				err := sk.FromHex(value)
+		err := sk.FromMaybeZeroHex(value)
 		if err != nil {
-					logError.Println("Failed to set private_key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set private_key: %w", err)
 		}
-				logDebug.Println("UAPI: Updating private key")
+		device.log.Verbosef("UAPI: Updating private key")
 		device.SetPrivateKey(sk)
 
 	case "listen_port":
-
-				// parse port number
-
 		port, err := strconv.ParseUint(value, 10, 16)
 		if err != nil {
-					logError.Println("Failed to parse listen_port:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to parse listen_port: %w", err)
 		}
 
 		// update port and rebind
-
-				logDebug.Println("UAPI: Updating listen port")
+		device.log.Verbosef("UAPI: Updating listen port")
 
 		device.net.Lock()
 		device.net.port = uint16(port)
 		device.net.Unlock()
 
 		if err := device.BindUpdate(); err != nil {
-					logError.Println("Failed to set listen_port:", err)
-					return &IPCError{ipc.IpcErrorPortInUse}
+			return ipcErrorf(ipc.IpcErrorPortInUse, "failed to set listen_port: %w", err)
 		}
 
 	case "fwmark":
-
-				// parse fwmark field
-
-				fwmark, err := func() (uint32, error) {
-					if value == "" {
-						return 0, nil
-					}
 		mark, err := strconv.ParseUint(value, 10, 32)
-					return uint32(mark), err
-				}()
-
 		if err != nil {
-					logError.Println("Invalid fwmark", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "invalid fwmark: %w", err)
 		}
 
-				logDebug.Println("UAPI: Updating fwmark")
-
-				if err := device.BindSetMark(uint32(fwmark)); err != nil {
-					logError.Println("Failed to update fwmark:", err)
-					return &IPCError{ipc.IpcErrorPortInUse}
+		device.log.Verbosef("UAPI: Updating fwmark")
+		if err := device.BindSetMark(uint32(mark)); err != nil {
+			return ipcErrorf(ipc.IpcErrorPortInUse, "failed to update fwmark: %w", err)
 		}
 
-			case "public_key":
-				// switch to peer configuration
-				logDebug.Println("UAPI: Transition to peer configuration")
-				deviceConfig = false
-
 	case "replace_peers":
 		if value != "true" {
-					logError.Println("Failed to set replace_peers, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set replace_peers, invalid value: %v", value)
 		}
-				logDebug.Println("UAPI: Removing all peers")
+		device.log.Verbosef("UAPI: Removing all peers")
 		device.RemoveAllPeers()
 
 	default:
-				logError.Println("Invalid UAPI device key:", key)
-				return &IPCError{ipc.IpcErrorInvalid}
-			}
+		return ipcErrorf(ipc.IpcErrorInvalid, "invalid UAPI device key: %v", key)
 	}
 
-		/* peer configuration */
+	return nil
+}
 
-		if !deviceConfig {
+// An ipcSetPeer is the current state of an IPC set operation on a peer.
+type ipcSetPeer struct {
+	*Peer        // Peer is the current peer being operated on
+	dummy   bool // dummy reports whether this peer is a temporary, placeholder peer
+	created bool // new reports whether this is a newly created peer
+}
 
-			switch key {
+func (peer *ipcSetPeer) handlePostConfig() {
+	if peer.Peer != nil && !peer.dummy && peer.Peer.device.isUp() {
+		peer.SendStagedPackets()
+	}
+}
 
-			case "public_key":
+func (device *Device) handlePublicKeyLine(peer *ipcSetPeer, value string) error {
+	// Load/create the peer we are configuring.
 	var publicKey NoisePublicKey
 	err := publicKey.FromHex(value)
 	if err != nil {
-					logError.Println("Failed to get peer by public key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+		return ipcErrorf(ipc.IpcErrorInvalid, "failed to get peer by public key: %w", err)
 	}
 
-				// ignore peer with public key of device
-
+	// Ignore peer with the same public key as this device.
 	device.staticIdentity.RLock()
-				dummy = device.staticIdentity.publicKey.Equals(publicKey)
+	peer.dummy = device.staticIdentity.publicKey.Equals(publicKey)
 	device.staticIdentity.RUnlock()
 
-				if dummy {
-					peer = &Peer{}
+	if peer.dummy {
+		peer.Peer = &Peer{}
 	} else {
-					peer = device.LookupPeer(publicKey)
+		peer.Peer = device.LookupPeer(publicKey)
 	}
 
-				if peer == nil {
-					peer, err = device.NewPeer(publicKey)
+	peer.created = peer.Peer == nil
+	if peer.created {
+		peer.Peer, err = device.NewPeer(publicKey)
 		if err != nil {
-						logError.Println("Failed to create new peer:", err)
-						return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to create new peer: %w", err)
 		}
-					logDebug.Println(peer, "- UAPI: Created")
+		device.log.Verbosef("%v - UAPI: Created", peer.Peer)
+	}
+	return nil
+}
+
+func (device *Device) handlePeerLine(peer *ipcSetPeer, key, value string) error {
+	switch key {
+	case "update_only":
+		// allow disabling of creation
+		if value != "true" {
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set update only, invalid value: %v", value)
+		}
+		if peer.created && !peer.dummy {
+			device.RemovePeer(peer.handshake.remoteStatic)
+			peer.Peer = &Peer{}
+			peer.dummy = true
 		}
 
 	case "remove":
-
 		// remove currently selected peer from device
-
 		if value != "true" {
-					logError.Println("Failed to set remove, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set remove, invalid value: %v", value)
 		}
-				if !dummy {
-					logDebug.Println(peer, "- UAPI: Removing")
+		if !peer.dummy {
+			device.log.Verbosef("%v - UAPI: Removing", peer.Peer)
 			device.RemovePeer(peer.handshake.remoteStatic)
 		}
-				peer = &Peer{}
-				dummy = true
+		peer.Peer = &Peer{}
+		peer.dummy = true
 
 	case "preshared_key":
-
-				// update PSK
-
-				logDebug.Println(peer, "- UAPI: Updating preshared key")
+		device.log.Verbosef("%v - UAPI: Updating preshared key", peer.Peer)
 
 		peer.handshake.mutex.Lock()
 		err := peer.handshake.presharedKey.FromHex(value)
 		peer.handshake.mutex.Unlock()
 
 		if err != nil {
-					logError.Println("Failed to set preshared key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set preshared key: %w", err)
 		}
 
 	case "endpoint":
-
-				// set endpoint destination
-
-				logDebug.Println(peer, "- UAPI: Updating endpoint")
-
-				err := func() error {
+		device.log.Verbosef("%v - UAPI: Updating endpoint", peer.Peer)
+		endpoint, err := conn.CreateEndpoint(value)
+		if err != nil {
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set endpoint %v: %w", value, err)
+		}
 		peer.Lock()
 		defer peer.Unlock()
-					endpoint, err := CreateEndpoint(value)
-					if err != nil {
-						return err
-					}
 		peer.endpoint = endpoint
-					return nil
-				}()
-
-				if err != nil {
-					logError.Println("Failed to set endpoint:", err, ":", value)
-					return &IPCError{ipc.IpcErrorInvalid}
-				}
 
 	case "persistent_keepalive_interval":
-
-				// update persistent keepalive interval
-
-				logDebug.Println(peer, "- UAPI: Updating persistent keepalive interval")
+		device.log.Verbosef("%v - UAPI: Updating persistent keepalive interval", peer.Peer)
 
 		secs, err := strconv.ParseUint(value, 10, 16)
 		if err != nil {
-					logError.Println("Failed to set persistent keepalive interval:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set persistent keepalive interval: %w", err)
 		}
 
-				old := peer.persistentKeepaliveInterval
-				peer.persistentKeepaliveInterval = uint16(secs)
-
-				// send immediate keepalive if we're turning it on and before it wasn't on
+		old := atomic.SwapUint32(&peer.persistentKeepaliveInterval, uint32(secs))
 
+		// Send immediate keepalive if we're turning it on and before it wasn't on.
 		if old == 0 && secs != 0 {
 			if err != nil {
-						logError.Println("Failed to get tun device status:", err)
-						return &IPCError{ipc.IpcErrorIO}
+				return ipcErrorf(ipc.IpcErrorIO, "failed to get tun device status: %w", err)
 			}
-					if device.isUp.Get() && !dummy {
+			if device.isUp() && !peer.dummy {
 				peer.SendKeepalive()
 			}
 		}
 
 	case "replace_allowed_ips":
-
-				logDebug.Println(peer, "- UAPI: Removing all allowedips")
-
+		device.log.Verbosef("%v - UAPI: Removing all allowedips", peer.Peer)
 		if value != "true" {
-					logError.Println("Failed to replace allowedips, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to replace allowedips, invalid value: %v", value)
 		}
-
-				if dummy {
-					continue
+		if peer.dummy {
+			return nil
 		}
-
-				device.allowedips.RemoveByPeer(peer)
+		device.allowedips.RemoveByPeer(peer.Peer)
 
 	case "allowed_ip":
-
-				logDebug.Println(peer, "- UAPI: Adding allowedip")
+		device.log.Verbosef("%v - UAPI: Adding allowedip", peer.Peer)
 
 		_, network, err := net.ParseCIDR(value)
 		if err != nil {
-					logError.Println("Failed to set allowed ip:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set allowed ip: %w", err)
 		}
-
-				if dummy {
-					continue
+		if peer.dummy {
+			return nil
 		}
-
 		ones, _ := network.Mask.Size()
-				device.allowedips.Insert(network.IP, uint(ones), peer)
+		device.allowedips.Insert(network.IP, uint(ones), peer.Peer)
 
 	case "protocol_version":
-
 		if value != "1" {
-					logError.Println("Invalid protocol version:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "invalid protocol version: %v", value)
 		}
 
 	default:
-				logError.Println("Invalid UAPI peer key:", key)
-				return &IPCError{ipc.IpcErrorInvalid}
-			}
-		}
+		return ipcErrorf(ipc.IpcErrorInvalid, "invalid UAPI peer key: %v", key)
 	}
 
 	return nil
 }
 
+func (device *Device) IpcGet() (string, error) {
+	buf := new(strings.Builder)
+	if err := device.IpcGetOperation(buf); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+func (device *Device) IpcSet(uapiConf string) error {
+	return device.IpcSetOperation(strings.NewReader(uapiConf))
+}
+
 func (device *Device) IpcHandle(socket net.Conn) {
-
-	// create buffered read/writer
-
 	defer socket.Close()
 
 	buffered := func(s io.ReadWriter) *bufio.ReadWriter {
@@ -386,35 +415,44 @@ func (device *Device) IpcHandle(socket net.Conn) {
 		return bufio.NewReadWriter(reader, writer)
 	}(socket)
 
-	defer buffered.Flush()
-
+	for {
 		op, err := buffered.ReadString('\n')
 		if err != nil {
 			return
 		}
 
 		// handle operation
-
-	var status *IPCError
-
 		switch op {
 		case "set=1\n":
-		status = device.IpcSetOperation(buffered.Reader)
-
+			err = device.IpcSetOperation(buffered.Reader)
 		case "get=1\n":
-		status = device.IpcGetOperation(buffered.Writer)
-
+			var nextByte byte
+			nextByte, err = buffered.ReadByte()
+			if err != nil {
+				return
+			}
+			if nextByte != '\n' {
+				err = ipcErrorf(ipc.IpcErrorInvalid, "trailing character in UAPI get: %q", nextByte)
+				break
+			}
+			err = device.IpcGetOperation(buffered.Writer)
 		default:
-		device.log.Error.Println("Invalid UAPI operation:", op)
+			device.log.Errorf("invalid UAPI operation: %v", op)
 			return
 		}
 
 		// write status
-
+		var status *IPCError
+		if err != nil && !errors.As(err, &status) {
+			// shouldn't happen
+			status = ipcErrorf(ipc.IpcErrorUnknown, "other UAPI error: %w", err)
+		}
 		if status != nil {
-		device.log.Error.Println(status)
+			device.log.Errorf("%v", status)
 			fmt.Fprintf(buffered, "errno=%d\n\n", status.ErrorCode())
 		} else {
 			fmt.Fprintf(buffered, "errno=0\n\n")
 		}
+		buffered.Flush()
+	}
 }

device/version.go

@@ -1,3 +0,0 @@
-package device
-
-const WireGuardGoVersion = "0.0.20190517"

donotuseon_linux.go

@@ -1,15 +0,0 @@
-// +build !android
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package main
-
-const DoNotUseThisProgramOnLinux = UseTheKernelModuleInstead
-
-// --------------------------------------------------------
-// Do not use this on Linux. Instead use the kernel module.
-// See wireguard.com/install for more information.
-// --------------------------------------------------------

go.mod

@@ -1,13 +1,9 @@
 module golang.zx2c4.com/wireguard
 
-go 1.12
+go 1.15
 
 require (
-	github.com/Microsoft/go-winio v0.4.12
-	github.com/pkg/errors v0.8.1 // indirect
-	golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734
-	golang.org/x/net v0.0.0-20190502183928-7f726cade0ab
-	golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82
+	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
+	golang.org/x/net v0.0.0-20201224014010-6772e930b67b
+	golang.org/x/sys v0.0.0-20210105210732-16f7687f5001
 )
-
-replace github.com/Microsoft/go-winio => golang.zx2c4.com/wireguard/windows v0.0.0-20190429060359-b01600290cd4

go.sum

@@ -1,15 +1,17 @@
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734 h1:p/H982KKEjUnLJkM3tt/LemDnOc1GiZL5FCVlORJ5zo=
-golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad h1:DN0cp81fZ3njFcrLCytUHRSUkqBjfTo4Tx9RJTWs0EY=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190502183928-7f726cade0ab h1:9RfW3ktsOZxgo9YNbBAjq1FWzc/igwEcUzZz8IXgSbk=
-golang.org/x/net v0.0.0-20190502183928-7f726cade0ab/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20201224014010-6772e930b67b h1:iFwSg7t5GZmB/Q5TjiEAsdoLDrdJRC1RiF2WhuV29Qw=
+golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82 h1:vsphBvatvfbhlb4PO1BYSr9dzugGxJ/SQHoNufZJq1w=
-golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210105210732-16f7687f5001 h1:/dSxr6gT0FNI1MO5WLJo8mTmItROeOKTkDn+7OwWBos=
+golang.org/x/sys v0.0.0-20210105210732-16f7687f5001/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.zx2c4.com/wireguard/windows v0.0.0-20190429060359-b01600290cd4 h1:wueYNew2pMLl/LcKqX4PAzc+zV4suK9+DJaZ8yIEHkM=
-golang.zx2c4.com/wireguard/windows v0.0.0-20190429060359-b01600290cd4/go.mod h1:Y+FYqVFaQO6a+1uigm0N0GiuaZrLEaBxEiJ8tfH9sMQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

ipc/uapi_bsd.go

@@ -2,32 +2,20 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
 
 import (
 	"errors"
-	"fmt"
 	"net"
 	"os"
-	"path"
 	"unsafe"
 
 	"golang.org/x/sys/unix"
 )
 
-var socketDirectory = "/var/run/wireguard"
-
-const (
-	IpcErrorIO        = -int64(unix.EIO)
-	IpcErrorProtocol  = -int64(unix.EPROTO)
-	IpcErrorInvalid   = -int64(unix.EINVAL)
-	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
-	socketName        = "%s.sock"
-)
-
 type UAPIListener struct {
 	listener net.Listener // unix socket listener
 	connNew  chan net.Conn
@@ -84,10 +72,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 		unixListener.SetUnlinkOnClose(true)
 	}
 
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
+	socketPath := sockPath(name)
 
 	// watch for deletion of socket
 
@@ -146,58 +131,3 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	return uapi, nil
 }
-
-func UAPIOpen(name string) (*os.File, error) {
-
-	// check if path exist
-
-	err := os.MkdirAll(socketDirectory, 0755)
-	if err != nil && !os.IsExist(err) {
-		return nil, err
-	}
-
-	// open UNIX socket
-
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
-
-	addr, err := net.ResolveUnixAddr("unix", socketPath)
-	if err != nil {
-		return nil, err
-	}
-
-	oldUmask := unix.Umask(0077)
-	listener, err := func() (*net.UnixListener, error) {
-
-		// initial connection attempt
-
-		listener, err := net.ListenUnix("unix", addr)
-		if err == nil {
-			return listener, nil
-		}
-
-		// check if socket already active
-
-		_, err = net.Dial("unix", socketPath)
-		if err == nil {
-			return nil, errors.New("unix socket in use")
-		}
-
-		// cleanup & attempt again
-
-		err = os.Remove(socketPath)
-		if err != nil {
-			return nil, err
-		}
-		return net.ListenUnix("unix", addr)
-	}()
-	unix.Umask(oldUmask)
-
-	if err != nil {
-		return nil, err
-	}
-
-	return listener.File()
-}

ipc/uapi_linux.go

@@ -1,31 +1,18 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
 
 import (
-	"errors"
-	"fmt"
 	"net"
 	"os"
-	"path"
 
 	"golang.org/x/sys/unix"
 	"golang.zx2c4.com/wireguard/rwcancel"
 )
 
-var socketDirectory = "/var/run/wireguard"
-
-const (
-	IpcErrorIO        = -int64(unix.EIO)
-	IpcErrorProtocol  = -int64(unix.EPROTO)
-	IpcErrorInvalid   = -int64(unix.EINVAL)
-	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
-	socketName        = "%s.sock"
-)
-
 type UAPIListener struct {
 	listener        net.Listener // unix socket listener
 	connNew         chan net.Conn
@@ -84,10 +71,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	// watch for deletion of socket
 
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
+	socketPath := sockPath(name)
 
 	uapi.inotifyFd, err = unix.InotifyInit()
 	if err != nil {
@@ -115,6 +99,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 	go func(l *UAPIListener) {
 		var buff [0]byte
 		for {
+			defer uapi.inotifyRWCancel.Close()
 			// start with lstat to avoid race condition
 			if _, err := os.Lstat(socketPath); os.IsNotExist(err) {
 				l.connErr <- err
@@ -143,58 +128,3 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	return uapi, nil
 }
-
-func UAPIOpen(name string) (*os.File, error) {
-
-	// check if path exist
-
-	err := os.MkdirAll(socketDirectory, 0755)
-	if err != nil && !os.IsExist(err) {
-		return nil, err
-	}
-
-	// open UNIX socket
-
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
-
-	addr, err := net.ResolveUnixAddr("unix", socketPath)
-	if err != nil {
-		return nil, err
-	}
-
-	oldUmask := unix.Umask(0077)
-	listener, err := func() (*net.UnixListener, error) {
-
-		// initial connection attempt
-
-		listener, err := net.ListenUnix("unix", addr)
-		if err == nil {
-			return listener, nil
-		}
-
-		// check if socket already active
-
-		_, err = net.Dial("unix", socketPath)
-		if err == nil {
-			return nil, errors.New("unix socket in use")
-		}
-
-		// cleanup & attempt again
-
-		err = os.Remove(socketPath)
-		if err != nil {
-			return nil, err
-		}
-		return net.ListenUnix("unix", addr)
-	}()
-	unix.Umask(oldUmask)
-
-	if err != nil {
-		return nil, err
-	}
-
-	return listener.File()
-}

ipc/uapi_unix.go

@@ -0,0 +1,66 @@
+// +build linux darwin freebsd openbsd
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package ipc
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	IpcErrorIO        = -int64(unix.EIO)
+	IpcErrorProtocol  = -int64(unix.EPROTO)
+	IpcErrorInvalid   = -int64(unix.EINVAL)
+	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
+	IpcErrorUnknown   = -55 // ENOANO
+)
+
+// socketDirectory is variable because it is modified by a linker
+// flag in wireguard-android.
+var socketDirectory = "/var/run/wireguard"
+
+func sockPath(iface string) string {
+	return fmt.Sprintf("%s/%s.sock", socketDirectory, iface)
+}
+
+func UAPIOpen(name string) (*os.File, error) {
+	if err := os.MkdirAll(socketDirectory, 0755); err != nil {
+		return nil, err
+	}
+
+	socketPath := sockPath(name)
+	addr, err := net.ResolveUnixAddr("unix", socketPath)
+	if err != nil {
+		return nil, err
+	}
+
+	oldUmask := unix.Umask(0077)
+	defer unix.Umask(oldUmask)
+
+	listener, err := net.ListenUnix("unix", addr)
+	if err == nil {
+		return listener.File()
+	}
+
+	// Test socket, if not in use cleanup and try again.
+	if _, err := net.Dial("unix", socketPath); err == nil {
+		return nil, errors.New("unix socket in use")
+	}
+	if err := os.Remove(socketPath); err != nil {
+		return nil, err
+	}
+	listener, err = net.ListenUnix("unix", addr)
+	if err != nil {
+		return nil, err
+	}
+	return listener.File()
+}

ipc/uapi_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
@@ -8,15 +8,18 @@ package ipc
 import (
 	"net"
 
-	"github.com/Microsoft/go-winio"
+	"golang.org/x/sys/windows"
+
+	"golang.zx2c4.com/wireguard/ipc/winpipe"
 )
 
-//TODO: replace these with actual standard windows error numbers from the win package
+// TODO: replace these with actual standard windows error numbers from the win package
 const (
 	IpcErrorIO        = -int64(5)
 	IpcErrorProtocol  = -int64(71)
 	IpcErrorInvalid   = -int64(22)
 	IpcErrorPortInUse = -int64(98)
+	IpcErrorUnknown   = -int64(55)
 )
 
 type UAPIListener struct {
@@ -47,22 +50,22 @@ func (l *UAPIListener) Addr() net.Addr {
 	return l.listener.Addr()
 }
 
-func GetSystemSecurityDescriptor() string {
-	//
-	// SDDL encoded.
-	//
-	// (system = SECURITY_NT_AUTHORITY | SECURITY_LOCAL_SYSTEM_RID)
-	// owner: system
-	// grant: GENERIC_ALL to system
-	//
-	return "O:SYD:(A;;GA;;;SY)"
+var UAPISecurityDescriptor *windows.SECURITY_DESCRIPTOR
+
+func init() {
+	var err error
+	/* SDDL_DEVOBJ_SYS_ALL from the WDK */
+	UAPISecurityDescriptor, err = windows.SecurityDescriptorFromString("O:SYD:P(A;;GA;;;SY)")
+	if err != nil {
+		panic(err)
+	}
 }
 
 func UAPIListen(name string) (net.Listener, error) {
-	config := winio.PipeConfig{
-		SecurityDescriptor: GetSystemSecurityDescriptor(),
+	config := winpipe.PipeConfig{
+		SecurityDescriptor: UAPISecurityDescriptor,
 	}
-	listener, err := winio.ListenPipe("\\\\.\\pipe\\WireGuard\\"+name, &config)
+	listener, err := winpipe.ListenPipe(`\\.\pipe\ProtectedPrefix\Administrators\WireGuard\`+name, &config)
 	if err != nil {
 		return nil, err
 	}

ipc/winpipe/file.go

@@ -0,0 +1,323 @@
+// +build windows
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2005 Microsoft
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+package winpipe
+
+import (
+	"errors"
+	"io"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"golang.org/x/sys/windows"
+)
+
+//sys cancelIoEx(file windows.Handle, o *windows.Overlapped) (err error) = CancelIoEx
+//sys createIoCompletionPort(file windows.Handle, port windows.Handle, key uintptr, threadCount uint32) (newport windows.Handle, err error) = CreateIoCompletionPort
+//sys getQueuedCompletionStatus(port windows.Handle, bytes *uint32, key *uintptr, o **ioOperation, timeout uint32) (err error) = GetQueuedCompletionStatus
+//sys setFileCompletionNotificationModes(h windows.Handle, flags uint8) (err error) = SetFileCompletionNotificationModes
+//sys wsaGetOverlappedResult(h windows.Handle, o *windows.Overlapped, bytes *uint32, wait bool, flags *uint32) (err error) = ws2_32.WSAGetOverlappedResult
+
+type atomicBool int32
+
+func (b *atomicBool) isSet() bool { return atomic.LoadInt32((*int32)(b)) != 0 }
+func (b *atomicBool) setFalse()   { atomic.StoreInt32((*int32)(b), 0) }
+func (b *atomicBool) setTrue()    { atomic.StoreInt32((*int32)(b), 1) }
+func (b *atomicBool) swap(new bool) bool {
+	var newInt int32
+	if new {
+		newInt = 1
+	}
+	return atomic.SwapInt32((*int32)(b), newInt) == 1
+}
+
+const (
+	cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS = 1
+	cFILE_SKIP_SET_EVENT_ON_HANDLE        = 2
+)
+
+var (
+	ErrFileClosed = errors.New("file has already been closed")
+	ErrTimeout    = &timeoutError{}
+)
+
+type timeoutError struct{}
+
+func (e *timeoutError) Error() string   { return "i/o timeout" }
+func (e *timeoutError) Timeout() bool   { return true }
+func (e *timeoutError) Temporary() bool { return true }
+
+type timeoutChan chan struct{}
+
+var ioInitOnce sync.Once
+var ioCompletionPort windows.Handle
+
+// ioResult contains the result of an asynchronous IO operation
+type ioResult struct {
+	bytes uint32
+	err   error
+}
+
+// ioOperation represents an outstanding asynchronous Win32 IO
+type ioOperation struct {
+	o  windows.Overlapped
+	ch chan ioResult
+}
+
+func initIo() {
+	h, err := createIoCompletionPort(windows.InvalidHandle, 0, 0, 0xffffffff)
+	if err != nil {
+		panic(err)
+	}
+	ioCompletionPort = h
+	go ioCompletionProcessor(h)
+}
+
+// win32File implements Reader, Writer, and Closer on a Win32 handle without blocking in a syscall.
+// It takes ownership of this handle and will close it if it is garbage collected.
+type win32File struct {
+	handle        windows.Handle
+	wg            sync.WaitGroup
+	wgLock        sync.RWMutex
+	closing       atomicBool
+	socket        bool
+	readDeadline  deadlineHandler
+	writeDeadline deadlineHandler
+}
+
+type deadlineHandler struct {
+	setLock     sync.Mutex
+	channel     timeoutChan
+	channelLock sync.RWMutex
+	timer       *time.Timer
+	timedout    atomicBool
+}
+
+// makeWin32File makes a new win32File from an existing file handle
+func makeWin32File(h windows.Handle) (*win32File, error) {
+	f := &win32File{handle: h}
+	ioInitOnce.Do(initIo)
+	_, err := createIoCompletionPort(h, ioCompletionPort, 0, 0xffffffff)
+	if err != nil {
+		return nil, err
+	}
+	err = setFileCompletionNotificationModes(h, cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS|cFILE_SKIP_SET_EVENT_ON_HANDLE)
+	if err != nil {
+		return nil, err
+	}
+	f.readDeadline.channel = make(timeoutChan)
+	f.writeDeadline.channel = make(timeoutChan)
+	return f, nil
+}
+
+func MakeOpenFile(h windows.Handle) (io.ReadWriteCloser, error) {
+	return makeWin32File(h)
+}
+
+// closeHandle closes the resources associated with a Win32 handle
+func (f *win32File) closeHandle() {
+	f.wgLock.Lock()
+	// Atomically set that we are closing, releasing the resources only once.
+	if !f.closing.swap(true) {
+		f.wgLock.Unlock()
+		// cancel all IO and wait for it to complete
+		cancelIoEx(f.handle, nil)
+		f.wg.Wait()
+		// at this point, no new IO can start
+		windows.Close(f.handle)
+		f.handle = 0
+	} else {
+		f.wgLock.Unlock()
+	}
+}
+
+// Close closes a win32File.
+func (f *win32File) Close() error {
+	f.closeHandle()
+	return nil
+}
+
+// prepareIo prepares for a new IO operation.
+// The caller must call f.wg.Done() when the IO is finished, prior to Close() returning.
+func (f *win32File) prepareIo() (*ioOperation, error) {
+	f.wgLock.RLock()
+	if f.closing.isSet() {
+		f.wgLock.RUnlock()
+		return nil, ErrFileClosed
+	}
+	f.wg.Add(1)
+	f.wgLock.RUnlock()
+	c := &ioOperation{}
+	c.ch = make(chan ioResult)
+	return c, nil
+}
+
+// ioCompletionProcessor processes completed async IOs forever
+func ioCompletionProcessor(h windows.Handle) {
+	for {
+		var bytes uint32
+		var key uintptr
+		var op *ioOperation
+		err := getQueuedCompletionStatus(h, &bytes, &key, &op, windows.INFINITE)
+		if op == nil {
+			panic(err)
+		}
+		op.ch <- ioResult{bytes, err}
+	}
+}
+
+// asyncIo processes the return value from ReadFile or WriteFile, blocking until
+// the operation has actually completed.
+func (f *win32File) asyncIo(c *ioOperation, d *deadlineHandler, bytes uint32, err error) (int, error) {
+	if err != windows.ERROR_IO_PENDING {
+		return int(bytes), err
+	}
+
+	if f.closing.isSet() {
+		cancelIoEx(f.handle, &c.o)
+	}
+
+	var timeout timeoutChan
+	if d != nil {
+		d.channelLock.Lock()
+		timeout = d.channel
+		d.channelLock.Unlock()
+	}
+
+	var r ioResult
+	select {
+	case r = <-c.ch:
+		err = r.err
+		if err == windows.ERROR_OPERATION_ABORTED {
+			if f.closing.isSet() {
+				err = ErrFileClosed
+			}
+		} else if err != nil && f.socket {
+			// err is from Win32. Query the overlapped structure to get the winsock error.
+			var bytes, flags uint32
+			err = wsaGetOverlappedResult(f.handle, &c.o, &bytes, false, &flags)
+		}
+	case <-timeout:
+		cancelIoEx(f.handle, &c.o)
+		r = <-c.ch
+		err = r.err
+		if err == windows.ERROR_OPERATION_ABORTED {
+			err = ErrTimeout
+		}
+	}
+
+	// runtime.KeepAlive is needed, as c is passed via native
+	// code to ioCompletionProcessor, c must remain alive
+	// until the channel read is complete.
+	runtime.KeepAlive(c)
+	return int(r.bytes), err
+}
+
+// Read reads from a file handle.
+func (f *win32File) Read(b []byte) (int, error) {
+	c, err := f.prepareIo()
+	if err != nil {
+		return 0, err
+	}
+	defer f.wg.Done()
+
+	if f.readDeadline.timedout.isSet() {
+		return 0, ErrTimeout
+	}
+
+	var bytes uint32
+	err = windows.ReadFile(f.handle, b, &bytes, &c.o)
+	n, err := f.asyncIo(c, &f.readDeadline, bytes, err)
+	runtime.KeepAlive(b)
+
+	// Handle EOF conditions.
+	if err == nil && n == 0 && len(b) != 0 {
+		return 0, io.EOF
+	} else if err == windows.ERROR_BROKEN_PIPE {
+		return 0, io.EOF
+	} else {
+		return n, err
+	}
+}
+
+// Write writes to a file handle.
+func (f *win32File) Write(b []byte) (int, error) {
+	c, err := f.prepareIo()
+	if err != nil {
+		return 0, err
+	}
+	defer f.wg.Done()
+
+	if f.writeDeadline.timedout.isSet() {
+		return 0, ErrTimeout
+	}
+
+	var bytes uint32
+	err = windows.WriteFile(f.handle, b, &bytes, &c.o)
+	n, err := f.asyncIo(c, &f.writeDeadline, bytes, err)
+	runtime.KeepAlive(b)
+	return n, err
+}
+
+func (f *win32File) SetReadDeadline(deadline time.Time) error {
+	return f.readDeadline.set(deadline)
+}
+
+func (f *win32File) SetWriteDeadline(deadline time.Time) error {
+	return f.writeDeadline.set(deadline)
+}
+
+func (f *win32File) Flush() error {
+	return windows.FlushFileBuffers(f.handle)
+}
+
+func (f *win32File) Fd() uintptr {
+	return uintptr(f.handle)
+}
+
+func (d *deadlineHandler) set(deadline time.Time) error {
+	d.setLock.Lock()
+	defer d.setLock.Unlock()
+
+	if d.timer != nil {
+		if !d.timer.Stop() {
+			<-d.channel
+		}
+		d.timer = nil
+	}
+	d.timedout.setFalse()
+
+	select {
+	case <-d.channel:
+		d.channelLock.Lock()
+		d.channel = make(chan struct{})
+		d.channelLock.Unlock()
+	default:
+	}
+
+	if deadline.IsZero() {
+		return nil
+	}
+
+	timeoutIO := func() {
+		d.timedout.setTrue()
+		close(d.channel)
+	}
+
+	now := time.Now()
+	duration := deadline.Sub(now)
+	if deadline.After(now) {
+		// Deadline is in the future, set a timer to wait
+		d.timer = time.AfterFunc(duration, timeoutIO)
+	} else {
+		// Deadline is in the past. Cancel all pending IO now.
+		timeoutIO()
+	}
+	return nil
+}

ipc/winpipe/mksyscall.go

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2005 Microsoft
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package winpipe
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go pipe.go file.go

ipc/winpipe/pipe.go

@@ -0,0 +1,509 @@
+// +build windows
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2005 Microsoft
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package winpipe
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"runtime"
+	"time"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+//sys connectNamedPipe(pipe windows.Handle, o *windows.Overlapped) (err error) = ConnectNamedPipe
+//sys createNamedPipe(name string, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *windows.SecurityAttributes) (handle windows.Handle, err error)  [failretval==windows.InvalidHandle] = CreateNamedPipeW
+//sys createFile(name string, access uint32, mode uint32, sa *windows.SecurityAttributes, createmode uint32, attrs uint32, templatefile windows.Handle) (handle windows.Handle, err error) [failretval==windows.InvalidHandle] = CreateFileW
+//sys getNamedPipeInfo(pipe windows.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) = GetNamedPipeInfo
+//sys getNamedPipeHandleState(pipe windows.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) = GetNamedPipeHandleStateW
+//sys localAlloc(uFlags uint32, length uint32) (ptr uintptr) = LocalAlloc
+//sys ntCreateNamedPipeFile(pipe *windows.Handle, access uint32, oa *objectAttributes, iosb *ioStatusBlock, share uint32, disposition uint32, options uint32, typ uint32, readMode uint32, completionMode uint32, maxInstances uint32, inboundQuota uint32, outputQuota uint32, timeout *int64) (status ntstatus) = ntdll.NtCreateNamedPipeFile
+//sys rtlNtStatusToDosError(status ntstatus) (winerr error) = ntdll.RtlNtStatusToDosErrorNoTeb
+//sys rtlDosPathNameToNtPathName(name *uint16, ntName *unicodeString, filePart uintptr, reserved uintptr) (status ntstatus) = ntdll.RtlDosPathNameToNtPathName_U
+//sys rtlDefaultNpAcl(dacl *uintptr) (status ntstatus) = ntdll.RtlDefaultNpAcl
+
+type ioStatusBlock struct {
+	Status, Information uintptr
+}
+
+type objectAttributes struct {
+	Length             uintptr
+	RootDirectory      uintptr
+	ObjectName         *unicodeString
+	Attributes         uintptr
+	SecurityDescriptor *windows.SECURITY_DESCRIPTOR
+	SecurityQoS        uintptr
+}
+
+type unicodeString struct {
+	Length        uint16
+	MaximumLength uint16
+	Buffer        uintptr
+}
+
+type ntstatus int32
+
+func (status ntstatus) Err() error {
+	if status >= 0 {
+		return nil
+	}
+	return rtlNtStatusToDosError(status)
+}
+
+const (
+	cSECURITY_SQOS_PRESENT = 0x100000
+	cSECURITY_ANONYMOUS    = 0
+
+	cPIPE_TYPE_MESSAGE = 4
+
+	cPIPE_READMODE_MESSAGE = 2
+
+	cFILE_OPEN   = 1
+	cFILE_CREATE = 2
+
+	cFILE_PIPE_MESSAGE_TYPE          = 1
+	cFILE_PIPE_REJECT_REMOTE_CLIENTS = 2
+)
+
+var (
+	// ErrPipeListenerClosed is returned for pipe operations on listeners that have been closed.
+	// This error should match net.errClosing since docker takes a dependency on its text.
+	ErrPipeListenerClosed = errors.New("use of closed network connection")
+
+	errPipeWriteClosed = errors.New("pipe has been closed for write")
+)
+
+type win32Pipe struct {
+	*win32File
+	path string
+}
+
+type win32MessageBytePipe struct {
+	win32Pipe
+	writeClosed bool
+	readEOF     bool
+}
+
+type pipeAddress string
+
+func (f *win32Pipe) LocalAddr() net.Addr {
+	return pipeAddress(f.path)
+}
+
+func (f *win32Pipe) RemoteAddr() net.Addr {
+	return pipeAddress(f.path)
+}
+
+func (f *win32Pipe) SetDeadline(t time.Time) error {
+	f.SetReadDeadline(t)
+	f.SetWriteDeadline(t)
+	return nil
+}
+
+// CloseWrite closes the write side of a message pipe in byte mode.
+func (f *win32MessageBytePipe) CloseWrite() error {
+	if f.writeClosed {
+		return errPipeWriteClosed
+	}
+	err := f.win32File.Flush()
+	if err != nil {
+		return err
+	}
+	_, err = f.win32File.Write(nil)
+	if err != nil {
+		return err
+	}
+	f.writeClosed = true
+	return nil
+}
+
+// Write writes bytes to a message pipe in byte mode. Zero-byte writes are ignored, since
+// they are used to implement CloseWrite().
+func (f *win32MessageBytePipe) Write(b []byte) (int, error) {
+	if f.writeClosed {
+		return 0, errPipeWriteClosed
+	}
+	if len(b) == 0 {
+		return 0, nil
+	}
+	return f.win32File.Write(b)
+}
+
+// Read reads bytes from a message pipe in byte mode. A read of a zero-byte message on a message
+// mode pipe will return io.EOF, as will all subsequent reads.
+func (f *win32MessageBytePipe) Read(b []byte) (int, error) {
+	if f.readEOF {
+		return 0, io.EOF
+	}
+	n, err := f.win32File.Read(b)
+	if err == io.EOF {
+		// If this was the result of a zero-byte read, then
+		// it is possible that the read was due to a zero-size
+		// message. Since we are simulating CloseWrite with a
+		// zero-byte message, ensure that all future Read() calls
+		// also return EOF.
+		f.readEOF = true
+	} else if err == windows.ERROR_MORE_DATA {
+		// ERROR_MORE_DATA indicates that the pipe's read mode is message mode
+		// and the message still has more bytes. Treat this as a success, since
+		// this package presents all named pipes as byte streams.
+		err = nil
+	}
+	return n, err
+}
+
+func (s pipeAddress) Network() string {
+	return "pipe"
+}
+
+func (s pipeAddress) String() string {
+	return string(s)
+}
+
+// tryDialPipe attempts to dial the pipe at `path` until `ctx` cancellation or timeout.
+func tryDialPipe(ctx context.Context, path *string) (windows.Handle, error) {
+	for {
+		select {
+		case <-ctx.Done():
+			return windows.Handle(0), ctx.Err()
+		default:
+			h, err := createFile(*path, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, windows.FILE_FLAG_OVERLAPPED|cSECURITY_SQOS_PRESENT|cSECURITY_ANONYMOUS, 0)
+			if err == nil {
+				return h, nil
+			}
+			if err != windows.ERROR_PIPE_BUSY {
+				return h, &os.PathError{Err: err, Op: "open", Path: *path}
+			}
+			// Wait 10 msec and try again. This is a rather simplistic
+			// view, as we always try each 10 milliseconds.
+			time.Sleep(time.Millisecond * 10)
+		}
+	}
+}
+
+// DialPipe connects to a named pipe by path, timing out if the connection
+// takes longer than the specified duration. If timeout is nil, then we use
+// a default timeout of 2 seconds.  (We do not use WaitNamedPipe.)
+func DialPipe(path string, timeout *time.Duration, expectedOwner *windows.SID) (net.Conn, error) {
+	var absTimeout time.Time
+	if timeout != nil {
+		absTimeout = time.Now().Add(*timeout)
+	} else {
+		absTimeout = time.Now().Add(time.Second * 2)
+	}
+	ctx, _ := context.WithDeadline(context.Background(), absTimeout)
+	conn, err := DialPipeContext(ctx, path, expectedOwner)
+	if err == context.DeadlineExceeded {
+		return nil, ErrTimeout
+	}
+	return conn, err
+}
+
+// DialPipeContext attempts to connect to a named pipe by `path` until `ctx`
+// cancellation or timeout.
+func DialPipeContext(ctx context.Context, path string, expectedOwner *windows.SID) (net.Conn, error) {
+	var err error
+	var h windows.Handle
+	h, err = tryDialPipe(ctx, &path)
+	if err != nil {
+		return nil, err
+	}
+
+	if expectedOwner != nil {
+		sd, err := windows.GetSecurityInfo(h, windows.SE_FILE_OBJECT, windows.OWNER_SECURITY_INFORMATION)
+		if err != nil {
+			windows.Close(h)
+			return nil, err
+		}
+		realOwner, _, err := sd.Owner()
+		if err != nil {
+			windows.Close(h)
+			return nil, err
+		}
+		if !realOwner.Equals(expectedOwner) {
+			windows.Close(h)
+			return nil, windows.ERROR_ACCESS_DENIED
+		}
+	}
+
+	var flags uint32
+	err = getNamedPipeInfo(h, &flags, nil, nil, nil)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+
+	f, err := makeWin32File(h)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+
+	// If the pipe is in message mode, return a message byte pipe, which
+	// supports CloseWrite().
+	if flags&cPIPE_TYPE_MESSAGE != 0 {
+		return &win32MessageBytePipe{
+			win32Pipe: win32Pipe{win32File: f, path: path},
+		}, nil
+	}
+	return &win32Pipe{win32File: f, path: path}, nil
+}
+
+type acceptResponse struct {
+	f   *win32File
+	err error
+}
+
+type win32PipeListener struct {
+	firstHandle windows.Handle
+	path        string
+	config      PipeConfig
+	acceptCh    chan (chan acceptResponse)
+	closeCh     chan int
+	doneCh      chan int
+}
+
+func makeServerPipeHandle(path string, sd *windows.SECURITY_DESCRIPTOR, c *PipeConfig, first bool) (windows.Handle, error) {
+	path16, err := windows.UTF16FromString(path)
+	if err != nil {
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+
+	var oa objectAttributes
+	oa.Length = unsafe.Sizeof(oa)
+
+	var ntPath unicodeString
+	if err := rtlDosPathNameToNtPathName(&path16[0], &ntPath, 0, 0).Err(); err != nil {
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+	defer windows.LocalFree(windows.Handle(ntPath.Buffer))
+	oa.ObjectName = &ntPath
+
+	// The security descriptor is only needed for the first pipe.
+	if first {
+		if sd != nil {
+			oa.SecurityDescriptor = sd
+		} else {
+			// Construct the default named pipe security descriptor.
+			var dacl uintptr
+			if err := rtlDefaultNpAcl(&dacl).Err(); err != nil {
+				return 0, fmt.Errorf("getting default named pipe ACL: %s", err)
+			}
+			defer windows.LocalFree(windows.Handle(dacl))
+			sd, err := windows.NewSecurityDescriptor()
+			if err != nil {
+				return 0, fmt.Errorf("creating new security descriptor: %s", err)
+			}
+			if err = sd.SetDACL((*windows.ACL)(unsafe.Pointer(dacl)), true, false); err != nil {
+				return 0, fmt.Errorf("assigning dacl: %s", err)
+			}
+			sd, err = sd.ToSelfRelative()
+			if err != nil {
+				return 0, fmt.Errorf("converting to self-relative: %s", err)
+			}
+			oa.SecurityDescriptor = sd
+		}
+	}
+
+	typ := uint32(cFILE_PIPE_REJECT_REMOTE_CLIENTS)
+	if c.MessageMode {
+		typ |= cFILE_PIPE_MESSAGE_TYPE
+	}
+
+	disposition := uint32(cFILE_OPEN)
+	access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE | windows.SYNCHRONIZE)
+	if first {
+		disposition = cFILE_CREATE
+		// By not asking for read or write access, the named pipe file system
+		// will put this pipe into an initially disconnected state, blocking
+		// client connections until the next call with first == false.
+		access = windows.SYNCHRONIZE
+	}
+
+	timeout := int64(-50 * 10000) // 50ms
+
+	var (
+		h    windows.Handle
+		iosb ioStatusBlock
+	)
+	err = ntCreateNamedPipeFile(&h, access, &oa, &iosb, windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE, disposition, 0, typ, 0, 0, 0xffffffff, uint32(c.InputBufferSize), uint32(c.OutputBufferSize), &timeout).Err()
+	if err != nil {
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+
+	runtime.KeepAlive(ntPath)
+	return h, nil
+}
+
+func (l *win32PipeListener) makeServerPipe() (*win32File, error) {
+	h, err := makeServerPipeHandle(l.path, nil, &l.config, false)
+	if err != nil {
+		return nil, err
+	}
+	f, err := makeWin32File(h)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+	return f, nil
+}
+
+func (l *win32PipeListener) makeConnectedServerPipe() (*win32File, error) {
+	p, err := l.makeServerPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	// Wait for the client to connect.
+	ch := make(chan error)
+	go func(p *win32File) {
+		ch <- connectPipe(p)
+	}(p)
+
+	select {
+	case err = <-ch:
+		if err != nil {
+			p.Close()
+			p = nil
+		}
+	case <-l.closeCh:
+		// Abort the connect request by closing the handle.
+		p.Close()
+		p = nil
+		err = <-ch
+		if err == nil || err == ErrFileClosed {
+			err = ErrPipeListenerClosed
+		}
+	}
+	return p, err
+}
+
+func (l *win32PipeListener) listenerRoutine() {
+	closed := false
+	for !closed {
+		select {
+		case <-l.closeCh:
+			closed = true
+		case responseCh := <-l.acceptCh:
+			var (
+				p   *win32File
+				err error
+			)
+			for {
+				p, err = l.makeConnectedServerPipe()
+				// If the connection was immediately closed by the client, try
+				// again.
+				if err != windows.ERROR_NO_DATA {
+					break
+				}
+			}
+			responseCh <- acceptResponse{p, err}
+			closed = err == ErrPipeListenerClosed
+		}
+	}
+	windows.Close(l.firstHandle)
+	l.firstHandle = 0
+	// Notify Close() and Accept() callers that the handle has been closed.
+	close(l.doneCh)
+}
+
+// PipeConfig contain configuration for the pipe listener.
+type PipeConfig struct {
+	// SecurityDescriptor contains a Windows security descriptor.
+	SecurityDescriptor *windows.SECURITY_DESCRIPTOR
+
+	// MessageMode determines whether the pipe is in byte or message mode. In either
+	// case the pipe is read in byte mode by default. The only practical difference in
+	// this implementation is that CloseWrite() is only supported for message mode pipes;
+	// CloseWrite() is implemented as a zero-byte write, but zero-byte writes are only
+	// transferred to the reader (and returned as io.EOF in this implementation)
+	// when the pipe is in message mode.
+	MessageMode bool
+
+	// InputBufferSize specifies the size the input buffer, in bytes.
+	InputBufferSize int32
+
+	// OutputBufferSize specifies the size the input buffer, in bytes.
+	OutputBufferSize int32
+}
+
+// ListenPipe creates a listener on a Windows named pipe path, e.g. \\.\pipe\mypipe.
+// The pipe must not already exist.
+func ListenPipe(path string, c *PipeConfig) (net.Listener, error) {
+	if c == nil {
+		c = &PipeConfig{}
+	}
+	h, err := makeServerPipeHandle(path, c.SecurityDescriptor, c, true)
+	if err != nil {
+		return nil, err
+	}
+	l := &win32PipeListener{
+		firstHandle: h,
+		path:        path,
+		config:      *c,
+		acceptCh:    make(chan (chan acceptResponse)),
+		closeCh:     make(chan int),
+		doneCh:      make(chan int),
+	}
+	go l.listenerRoutine()
+	return l, nil
+}
+
+func connectPipe(p *win32File) error {
+	c, err := p.prepareIo()
+	if err != nil {
+		return err
+	}
+	defer p.wg.Done()
+
+	err = connectNamedPipe(p.handle, &c.o)
+	_, err = p.asyncIo(c, nil, 0, err)
+	if err != nil && err != windows.ERROR_PIPE_CONNECTED {
+		return err
+	}
+	return nil
+}
+
+func (l *win32PipeListener) Accept() (net.Conn, error) {
+	ch := make(chan acceptResponse)
+	select {
+	case l.acceptCh <- ch:
+		response := <-ch
+		err := response.err
+		if err != nil {
+			return nil, err
+		}
+		if l.config.MessageMode {
+			return &win32MessageBytePipe{
+				win32Pipe: win32Pipe{win32File: response.f, path: l.path},
+			}, nil
+		}
+		return &win32Pipe{win32File: response.f, path: l.path}, nil
+	case <-l.doneCh:
+		return nil, ErrPipeListenerClosed
+	}
+}
+
+func (l *win32PipeListener) Close() error {
+	select {
+	case l.closeCh <- 1:
+		<-l.doneCh
+	case <-l.doneCh:
+	}
+	return nil
+}
+
+func (l *win32PipeListener) Addr() net.Addr {
+	return pipeAddress(l.path)
+}

ipc/winpipe/zsyscall_windows.go

@@ -0,0 +1,238 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package winpipe
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return nil
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modkernel32 = windows.NewLazySystemDLL("kernel32.dll")
+	modntdll    = windows.NewLazySystemDLL("ntdll.dll")
+	modws2_32   = windows.NewLazySystemDLL("ws2_32.dll")
+
+	procConnectNamedPipe                   = modkernel32.NewProc("ConnectNamedPipe")
+	procCreateNamedPipeW                   = modkernel32.NewProc("CreateNamedPipeW")
+	procCreateFileW                        = modkernel32.NewProc("CreateFileW")
+	procGetNamedPipeInfo                   = modkernel32.NewProc("GetNamedPipeInfo")
+	procGetNamedPipeHandleStateW           = modkernel32.NewProc("GetNamedPipeHandleStateW")
+	procLocalAlloc                         = modkernel32.NewProc("LocalAlloc")
+	procNtCreateNamedPipeFile              = modntdll.NewProc("NtCreateNamedPipeFile")
+	procRtlNtStatusToDosErrorNoTeb         = modntdll.NewProc("RtlNtStatusToDosErrorNoTeb")
+	procRtlDosPathNameToNtPathName_U       = modntdll.NewProc("RtlDosPathNameToNtPathName_U")
+	procRtlDefaultNpAcl                    = modntdll.NewProc("RtlDefaultNpAcl")
+	procCancelIoEx                         = modkernel32.NewProc("CancelIoEx")
+	procCreateIoCompletionPort             = modkernel32.NewProc("CreateIoCompletionPort")
+	procGetQueuedCompletionStatus          = modkernel32.NewProc("GetQueuedCompletionStatus")
+	procSetFileCompletionNotificationModes = modkernel32.NewProc("SetFileCompletionNotificationModes")
+	procWSAGetOverlappedResult             = modws2_32.NewProc("WSAGetOverlappedResult")
+)
+
+func connectNamedPipe(pipe windows.Handle, o *windows.Overlapped) (err error) {
+	r1, _, e1 := syscall.Syscall(procConnectNamedPipe.Addr(), 2, uintptr(pipe), uintptr(unsafe.Pointer(o)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func createNamedPipe(name string, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *windows.SecurityAttributes) (handle windows.Handle, err error) {
+	var _p0 *uint16
+	_p0, err = syscall.UTF16PtrFromString(name)
+	if err != nil {
+		return
+	}
+	return _createNamedPipe(_p0, flags, pipeMode, maxInstances, outSize, inSize, defaultTimeout, sa)
+}
+
+func _createNamedPipe(name *uint16, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *windows.SecurityAttributes) (handle windows.Handle, err error) {
+	r0, _, e1 := syscall.Syscall9(procCreateNamedPipeW.Addr(), 8, uintptr(unsafe.Pointer(name)), uintptr(flags), uintptr(pipeMode), uintptr(maxInstances), uintptr(outSize), uintptr(inSize), uintptr(defaultTimeout), uintptr(unsafe.Pointer(sa)), 0)
+	handle = windows.Handle(r0)
+	if handle == windows.InvalidHandle {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func createFile(name string, access uint32, mode uint32, sa *windows.SecurityAttributes, createmode uint32, attrs uint32, templatefile windows.Handle) (handle windows.Handle, err error) {
+	var _p0 *uint16
+	_p0, err = syscall.UTF16PtrFromString(name)
+	if err != nil {
+		return
+	}
+	return _createFile(_p0, access, mode, sa, createmode, attrs, templatefile)
+}
+
+func _createFile(name *uint16, access uint32, mode uint32, sa *windows.SecurityAttributes, createmode uint32, attrs uint32, templatefile windows.Handle) (handle windows.Handle, err error) {
+	r0, _, e1 := syscall.Syscall9(procCreateFileW.Addr(), 7, uintptr(unsafe.Pointer(name)), uintptr(access), uintptr(mode), uintptr(unsafe.Pointer(sa)), uintptr(createmode), uintptr(attrs), uintptr(templatefile), 0, 0)
+	handle = windows.Handle(r0)
+	if handle == windows.InvalidHandle {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getNamedPipeInfo(pipe windows.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetNamedPipeInfo.Addr(), 5, uintptr(pipe), uintptr(unsafe.Pointer(flags)), uintptr(unsafe.Pointer(outSize)), uintptr(unsafe.Pointer(inSize)), uintptr(unsafe.Pointer(maxInstances)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getNamedPipeHandleState(pipe windows.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) {
+	r1, _, e1 := syscall.Syscall9(procGetNamedPipeHandleStateW.Addr(), 7, uintptr(pipe), uintptr(unsafe.Pointer(state)), uintptr(unsafe.Pointer(curInstances)), uintptr(unsafe.Pointer(maxCollectionCount)), uintptr(unsafe.Pointer(collectDataTimeout)), uintptr(unsafe.Pointer(userName)), uintptr(maxUserNameSize), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func localAlloc(uFlags uint32, length uint32) (ptr uintptr) {
+	r0, _, _ := syscall.Syscall(procLocalAlloc.Addr(), 2, uintptr(uFlags), uintptr(length), 0)
+	ptr = uintptr(r0)
+	return
+}
+
+func ntCreateNamedPipeFile(pipe *windows.Handle, access uint32, oa *objectAttributes, iosb *ioStatusBlock, share uint32, disposition uint32, options uint32, typ uint32, readMode uint32, completionMode uint32, maxInstances uint32, inboundQuota uint32, outputQuota uint32, timeout *int64) (status ntstatus) {
+	r0, _, _ := syscall.Syscall15(procNtCreateNamedPipeFile.Addr(), 14, uintptr(unsafe.Pointer(pipe)), uintptr(access), uintptr(unsafe.Pointer(oa)), uintptr(unsafe.Pointer(iosb)), uintptr(share), uintptr(disposition), uintptr(options), uintptr(typ), uintptr(readMode), uintptr(completionMode), uintptr(maxInstances), uintptr(inboundQuota), uintptr(outputQuota), uintptr(unsafe.Pointer(timeout)), 0)
+	status = ntstatus(r0)
+	return
+}
+
+func rtlNtStatusToDosError(status ntstatus) (winerr error) {
+	r0, _, _ := syscall.Syscall(procRtlNtStatusToDosErrorNoTeb.Addr(), 1, uintptr(status), 0, 0)
+	if r0 != 0 {
+		winerr = syscall.Errno(r0)
+	}
+	return
+}
+
+func rtlDosPathNameToNtPathName(name *uint16, ntName *unicodeString, filePart uintptr, reserved uintptr) (status ntstatus) {
+	r0, _, _ := syscall.Syscall6(procRtlDosPathNameToNtPathName_U.Addr(), 4, uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(ntName)), uintptr(filePart), uintptr(reserved), 0, 0)
+	status = ntstatus(r0)
+	return
+}
+
+func rtlDefaultNpAcl(dacl *uintptr) (status ntstatus) {
+	r0, _, _ := syscall.Syscall(procRtlDefaultNpAcl.Addr(), 1, uintptr(unsafe.Pointer(dacl)), 0, 0)
+	status = ntstatus(r0)
+	return
+}
+
+func cancelIoEx(file windows.Handle, o *windows.Overlapped) (err error) {
+	r1, _, e1 := syscall.Syscall(procCancelIoEx.Addr(), 2, uintptr(file), uintptr(unsafe.Pointer(o)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func createIoCompletionPort(file windows.Handle, port windows.Handle, key uintptr, threadCount uint32) (newport windows.Handle, err error) {
+	r0, _, e1 := syscall.Syscall6(procCreateIoCompletionPort.Addr(), 4, uintptr(file), uintptr(port), uintptr(key), uintptr(threadCount), 0, 0)
+	newport = windows.Handle(r0)
+	if newport == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func getQueuedCompletionStatus(port windows.Handle, bytes *uint32, key *uintptr, o **ioOperation, timeout uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procGetQueuedCompletionStatus.Addr(), 5, uintptr(port), uintptr(unsafe.Pointer(bytes)), uintptr(unsafe.Pointer(key)), uintptr(unsafe.Pointer(o)), uintptr(timeout), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func setFileCompletionNotificationModes(h windows.Handle, flags uint8) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetFileCompletionNotificationModes.Addr(), 2, uintptr(h), uintptr(flags), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func wsaGetOverlappedResult(h windows.Handle, o *windows.Overlapped, bytes *uint32, wait bool, flags *uint32) (err error) {
+	var _p0 uint32
+	if wait {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r1, _, e1 := syscall.Syscall6(procWSAGetOverlappedResult.Addr(), 5, uintptr(h), uintptr(unsafe.Pointer(o)), uintptr(unsafe.Pointer(bytes)), uintptr(_p0), uintptr(unsafe.Pointer(flags)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}

main.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package main
@@ -40,43 +40,27 @@ func warning() {
 	if runtime.GOOS != "linux" || os.Getenv(ENV_WG_PROCESS_FOREGROUND) == "1" {
 		return
 	}
-	shouldQuit := os.Getenv("WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD") != "1"
 
-	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
-	fmt.Fprintln(os.Stderr, "W                                                     G")
-	fmt.Fprintln(os.Stderr, "W   You are running this software on a Linux kernel,  G")
-	fmt.Fprintln(os.Stderr, "W   which is probably unnecessary and foolish. This   G")
-	fmt.Fprintln(os.Stderr, "W   is because the Linux kernel has built-in first    G")
-	fmt.Fprintln(os.Stderr, "W   class support for WireGuard, and this support is  G")
-	fmt.Fprintln(os.Stderr, "W   much more refined than this slower userspace      G")
-	fmt.Fprintln(os.Stderr, "W   implementation. For more information on           G")
-	fmt.Fprintln(os.Stderr, "W   installing the kernel module, please visit:       G")
-	fmt.Fprintln(os.Stderr, "W           https://www.wireguard.com/install         G")
-	if shouldQuit {
-		fmt.Fprintln(os.Stderr, "W                                                     G")
-		fmt.Fprintln(os.Stderr, "W   If you still want to use this program, against    G")
-		fmt.Fprintln(os.Stderr, "W   the advice here, please first export this         G")
-		fmt.Fprintln(os.Stderr, "W   environment variable:                             G")
-		fmt.Fprintln(os.Stderr, "W   WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1    G")
-	}
-	fmt.Fprintln(os.Stderr, "W                                                     G")
-	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
-
-	if shouldQuit {
-		os.Exit(1)
-	}
+	fmt.Fprintln(os.Stderr, "┌───────────────────────────────────────────────────┐")
+	fmt.Fprintln(os.Stderr, "│                                                   │")
+	fmt.Fprintln(os.Stderr, "│   Running this software on Linux is unnecessary,  │")
+	fmt.Fprintln(os.Stderr, "│   because the Linux kernel has built-in first     │")
+	fmt.Fprintln(os.Stderr, "│   class support for WireGuard, which will be      │")
+	fmt.Fprintln(os.Stderr, "│   faster, slicker, and better integrated. For     │")
+	fmt.Fprintln(os.Stderr, "│   information on installing the kernel module,    │")
+	fmt.Fprintln(os.Stderr, "│   please visit: <https://wireguard.com/install>.  │")
+	fmt.Fprintln(os.Stderr, "│                                                   │")
+	fmt.Fprintln(os.Stderr, "└───────────────────────────────────────────────────┘")
 }
 
 func main() {
 	if len(os.Args) == 2 && os.Args[1] == "--version" {
-		fmt.Printf("wireguard-go v%s\n\nUserspace WireGuard daemon for %s-%s.\nInformation available at https://www.wireguard.com.\nCopyright (C) Jason A. Donenfeld <Jason@zx2c4.com>.\n", device.WireGuardGoVersion, runtime.GOOS, runtime.GOARCH)
+		fmt.Printf("wireguard-go v%s\n\nUserspace WireGuard daemon for %s-%s.\nInformation available at https://www.wireguard.com.\nCopyright (C) Jason A. Donenfeld <Jason@zx2c4.com>.\n", Version, runtime.GOOS, runtime.GOARCH)
 		return
 	}
 
 	warning()
 
-	// parse arguments
-
 	var foreground bool
 	var interfaceName string
 	if len(os.Args) < 2 || len(os.Args) > 3 {
@@ -111,21 +95,19 @@ func main() {
 
 	logLevel := func() int {
 		switch os.Getenv("LOG_LEVEL") {
-		case "debug":
-			return device.LogLevelDebug
-		case "info":
-			return device.LogLevelInfo
+		case "verbose", "debug":
+			return device.LogLevelVerbose
 		case "error":
 			return device.LogLevelError
 		case "silent":
 			return device.LogLevelSilent
 		}
-		return device.LogLevelInfo
+		return device.LogLevelError
 	}()
 
 	// open TUN device (or use supplied fd)
 
-	tun, err := func() (tun.TUNDevice, error) {
+	tun, err := func() (tun.Device, error) {
 		tunFdStr := os.Getenv(ENV_WG_TUN_FD)
 		if tunFdStr == "" {
 			return tun.CreateTUN(interfaceName, device.DefaultMTU)
@@ -159,12 +141,10 @@ func main() {
 		fmt.Sprintf("(%s) ", interfaceName),
 	)
 
-	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
-
-	logger.Debug.Println("Debug log enabled")
+	logger.Verbosef("Starting wireguard-go version %s", Version)
 
 	if err != nil {
-		logger.Error.Println("Failed to create TUN device:", err)
+		logger.Errorf("Failed to create TUN device: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -187,7 +167,7 @@ func main() {
 	}()
 
 	if err != nil {
-		logger.Error.Println("UAPI listen error:", err)
+		logger.Errorf("UAPI listen error: %v", err)
 		os.Exit(ExitSetupFailed)
 		return
 	}
@@ -222,7 +202,7 @@ func main() {
 
 		path, err := os.Executable()
 		if err != nil {
-			logger.Error.Println("Failed to determine executable:", err)
+			logger.Errorf("Failed to determine executable: %v", err)
 			os.Exit(ExitSetupFailed)
 		}
 
@@ -232,7 +212,7 @@ func main() {
 			attr,
 		)
 		if err != nil {
-			logger.Error.Println("Failed to daemonize:", err)
+			logger.Errorf("Failed to daemonize: %v", err)
 			os.Exit(ExitSetupFailed)
 		}
 		process.Release()
@@ -241,14 +221,14 @@ func main() {
 
 	device := device.NewDevice(tun, logger)
 
-	logger.Info.Println("Device started")
+	logger.Verbosef("Device started")
 
 	errs := make(chan error)
 	term := make(chan os.Signal, 1)
 
 	uapi, err := ipc.UAPIListen(interfaceName, fileUAPI)
 	if err != nil {
-		logger.Error.Println("Failed to listen on uapi socket:", err)
+		logger.Errorf("Failed to listen on uapi socket: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -263,7 +243,7 @@ func main() {
 		}
 	}()
 
-	logger.Info.Println("UAPI listener started")
+	logger.Verbosef("UAPI listener started")
 
 	// wait for program to terminate
 
@@ -281,5 +261,5 @@ func main() {
 	uapi.Close()
 	device.Close()
 
-	logger.Info.Println("Shutting down")
+	logger.Verbosef("Shutting down")
 }

main_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package main
@@ -31,30 +31,33 @@ func main() {
 	fmt.Fprintln(os.Stderr, "Warning: this is a test program for Windows, mainly used for debugging this Go package. For a real WireGuard for Windows client, the repo you want is <https://git.zx2c4.com/wireguard-windows/>, which includes this code as a module.")
 
 	logger := device.NewLogger(
-		device.LogLevelDebug,
+		device.LogLevelVerbose,
 		fmt.Sprintf("(%s) ", interfaceName),
 	)
-	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
-	logger.Debug.Println("Debug log enabled")
+	logger.Verbosef("Starting wireguard-go version %s", Version)
 
-	tun, err := tun.CreateTUN(interfaceName)
+	tun, err := tun.CreateTUN(interfaceName, 0)
 	if err == nil {
 		realInterfaceName, err2 := tun.Name()
 		if err2 == nil {
 			interfaceName = realInterfaceName
 		}
 	} else {
-		logger.Error.Println("Failed to create TUN device:", err)
+		logger.Errorf("Failed to create TUN device: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
 	device := device.NewDevice(tun, logger)
-	device.Up()
-	logger.Info.Println("Device started")
+	err = device.Up()
+	if err != nil {
+		logger.Errorf("Failed to bring up device: %v", err)
+		os.Exit(ExitSetupFailed)
+	}
+	logger.Verbosef("Device started")
 
 	uapi, err := ipc.UAPIListen(interfaceName)
 	if err != nil {
-		logger.Error.Println("Failed to listen on uapi socket:", err)
+		logger.Errorf("Failed to listen on uapi socket: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -71,7 +74,7 @@ func main() {
 			go device.IpcHandle(conn)
 		}
 	}()
-	logger.Info.Println("UAPI listener started")
+	logger.Verbosef("UAPI listener started")
 
 	// wait for program to terminate
 
@@ -90,5 +93,5 @@ func main() {
 	uapi.Close()
 	device.Close()
 
-	logger.Info.Println("Shutting down")
+	logger.Verbosef("Shutting down")
 }

ratelimiter/ratelimiter.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ratelimiter
@@ -20,21 +20,23 @@ const (
 )
 
 type RatelimiterEntry struct {
-	sync.Mutex
+	mu       sync.Mutex
 	lastTime time.Time
 	tokens   int64
 }
 
 type Ratelimiter struct {
-	sync.RWMutex
-	stopReset chan struct{}
+	mu      sync.RWMutex
+	timeNow func() time.Time
+
+	stopReset chan struct{} // send to reset, close to stop
 	tableIPv4 map[[net.IPv4len]byte]*RatelimiterEntry
 	tableIPv6 map[[net.IPv6len]byte]*RatelimiterEntry
 }
 
 func (rate *Ratelimiter) Close() {
-	rate.Lock()
-	defer rate.Unlock()
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
 
 	if rate.stopReset != nil {
 		close(rate.stopReset)
@@ -42,11 +44,14 @@ func (rate *Ratelimiter) Close() {
 }
 
 func (rate *Ratelimiter) Init() {
-	rate.Lock()
-	defer rate.Unlock()
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
+
+	if rate.timeNow == nil {
+		rate.timeNow = time.Now
+	}
 
 	// stop any ongoing garbage collection routine
-
 	if rate.stopReset != nil {
 		close(rate.stopReset)
 	}
@@ -55,48 +60,50 @@ func (rate *Ratelimiter) Init() {
 	rate.tableIPv4 = make(map[[net.IPv4len]byte]*RatelimiterEntry)
 	rate.tableIPv6 = make(map[[net.IPv6len]byte]*RatelimiterEntry)
 
-	// start garbage collection routine
+	stopReset := rate.stopReset // store in case Init is called again.
 
+	// Start garbage collection routine.
 	go func() {
 		ticker := time.NewTicker(time.Second)
 		ticker.Stop()
 		for {
 			select {
-			case _, ok := <-rate.stopReset:
+			case _, ok := <-stopReset:
 				ticker.Stop()
-				if ok {
-					ticker = time.NewTicker(time.Second)
-				} else {
+				if !ok {
 					return
 				}
+				ticker = time.NewTicker(time.Second)
 			case <-ticker.C:
-				func() {
-					rate.Lock()
-					defer rate.Unlock()
+				if rate.cleanup() {
+					ticker.Stop()
+				}
+			}
+		}
+	}()
+}
+
+func (rate *Ratelimiter) cleanup() (empty bool) {
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
 
 	for key, entry := range rate.tableIPv4 {
-						entry.Lock()
-						if time.Now().Sub(entry.lastTime) > garbageCollectTime {
+		entry.mu.Lock()
+		if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
 			delete(rate.tableIPv4, key)
 		}
-						entry.Unlock()
+		entry.mu.Unlock()
 	}
 
 	for key, entry := range rate.tableIPv6 {
-						entry.Lock()
-						if time.Now().Sub(entry.lastTime) > garbageCollectTime {
+		entry.mu.Lock()
+		if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
 			delete(rate.tableIPv6, key)
 		}
-						entry.Unlock()
+		entry.mu.Unlock()
 	}
 
-					if len(rate.tableIPv4) == 0 && len(rate.tableIPv6) == 0 {
-						ticker.Stop()
-					}
-				}()
-			}
-		}
-	}()
+	return len(rate.tableIPv4) == 0 && len(rate.tableIPv6) == 0
 }
 
 func (rate *Ratelimiter) Allow(ip net.IP) bool {
@@ -109,7 +116,7 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 	IPv4 := ip.To4()
 	IPv6 := ip.To16()
 
-	rate.RLock()
+	rate.mu.RLock()
 
 	if IPv4 != nil {
 		copy(keyIPv4[:], IPv4)
@@ -119,15 +126,15 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 		entry = rate.tableIPv6[keyIPv6]
 	}
 
-	rate.RUnlock()
+	rate.mu.RUnlock()
 
 	// make new entry if not found
 
 	if entry == nil {
 		entry = new(RatelimiterEntry)
 		entry.tokens = maxTokens - packetCost
-		entry.lastTime = time.Now()
-		rate.Lock()
+		entry.lastTime = rate.timeNow()
+		rate.mu.Lock()
 		if IPv4 != nil {
 			rate.tableIPv4[keyIPv4] = entry
 			if len(rate.tableIPv4) == 1 && len(rate.tableIPv6) == 0 {
@@ -139,14 +146,14 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 				rate.stopReset <- struct{}{}
 			}
 		}
-		rate.Unlock()
+		rate.mu.Unlock()
 		return true
 	}
 
 	// add tokens to entry
 
-	entry.Lock()
-	now := time.Now()
+	entry.mu.Lock()
+	now := rate.timeNow()
 	entry.tokens += now.Sub(entry.lastTime).Nanoseconds()
 	entry.lastTime = now
 	if entry.tokens > maxTokens {
@@ -157,9 +164,9 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 
 	if entry.tokens > packetCost {
 		entry.tokens -= packetCost
-		entry.Unlock()
+		entry.mu.Unlock()
 		return true
 	}
-	entry.Unlock()
+	entry.mu.Unlock()
 	return false
 }

ratelimiter/ratelimiter_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ratelimiter
@@ -11,22 +11,21 @@ import (
 	"time"
 )
 
-type RatelimiterResult struct {
+type result struct {
 	allowed bool
 	text    string
 	wait    time.Duration
 }
 
 func TestRatelimiter(t *testing.T) {
+	var rate Ratelimiter
+	var expectedResults []result
 
-	var ratelimiter Ratelimiter
-	var expectedResults []RatelimiterResult
-
-	Nano := func(nano int64) time.Duration {
+	nano := func(nano int64) time.Duration {
 		return time.Nanosecond * time.Duration(nano)
 	}
 
-	Add := func(res RatelimiterResult) {
+	add := func(res result) {
 		expectedResults = append(
 			expectedResults,
 			res,
@@ -34,40 +33,40 @@ func TestRatelimiter(t *testing.T) {
 	}
 
 	for i := 0; i < packetsBurstable; i++ {
-		Add(RatelimiterResult{
+		add(result{
 			allowed: true,
-			text:    "inital burst",
+			text:    "initial burst",
 		})
 	}
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "after burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
-		wait:    Nano(time.Second.Nanoseconds() / packetsPerSecond),
+		wait:    nano(time.Second.Nanoseconds() / packetsPerSecond),
 		text:    "filling tokens for single packet",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "not having refilled enough",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
-		wait:    2 * (Nano(time.Second.Nanoseconds() / packetsPerSecond)),
+		wait:    2 * (nano(time.Second.Nanoseconds() / packetsPerSecond)),
 		text:    "filling tokens for two packet burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
 		text:    "second packet in 2 packet burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "packet following 2 packet burst",
 	})
@@ -89,14 +88,31 @@ func TestRatelimiter(t *testing.T) {
 		net.ParseIP("3f0e:54a2:f5b4:cd19:a21d:58e1:3746:84c4"),
 	}
 
-	ratelimiter.Init()
+	now := time.Now()
+	rate.timeNow = func() time.Time {
+		return now
+	}
+	defer func() {
+		// Lock to avoid data race with cleanup goroutine from Init.
+		rate.mu.Lock()
+		defer rate.mu.Unlock()
+
+		rate.timeNow = time.Now
+	}()
+	timeSleep := func(d time.Duration) {
+		now = now.Add(d + 1)
+		rate.cleanup()
+	}
+
+	rate.Init()
+	defer rate.Close()
 
 	for i, res := range expectedResults {
-		time.Sleep(res.wait)
+		timeSleep(res.wait)
 		for _, ip := range ips {
-			allowed := ratelimiter.Allow(ip)
+			allowed := rate.Allow(ip)
 			if allowed != res.allowed {
-				t.Fatal("Test failed for", ip.String(), ", on:", i, "(", res.text, ")", "expected:", res.allowed, "got:", allowed)
+				t.Fatalf("%d: %s: rate.Allow(%q)=%v, want %v", i, res.text, ip, allowed, res.allowed)
 			}
 		}
 	}

replay/replay.go

@@ -1,83 +1,62 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
+// Package replay implements an efficient anti-replay algorithm as specified in RFC 6479.
 package replay
 
-/* Implementation of RFC6479
- * https://tools.ietf.org/html/rfc6479
- *
- * The implementation is not safe for concurrent use!
- */
+type block uint64
 
 const (
-	// See: https://golang.org/src/math/big/arith.go
-	_Wordm       = ^uintptr(0)
-	_WordLogSize = _Wordm>>8&1 + _Wordm>>16&1 + _Wordm>>32&1
-	_WordSize    = 1 << _WordLogSize
+	blockBitLog = 6                // 1<<6 == 64 bits
+	blockBits   = 1 << blockBitLog // must be power of 2
+	ringBlocks  = 1 << 7           // must be power of 2
+	windowSize  = (ringBlocks - 1) * blockBits
+	blockMask   = ringBlocks - 1
+	bitMask     = blockBits - 1
 )
 
-const (
-	CounterRedundantBitsLog = _WordLogSize + 3
-	CounterRedundantBits    = _WordSize * 8
-	CounterBitsTotal        = 2048
-	CounterWindowSize       = uint64(CounterBitsTotal - CounterRedundantBits)
-)
-
-const (
-	BacktrackWords = CounterBitsTotal / _WordSize
-)
-
-func minUint64(a uint64, b uint64) uint64 {
-	if a > b {
-		return b
-	}
-	return a
+// A Filter rejects replayed messages by checking if message counter value is
+// within a sliding window of previously received messages.
+// The zero value for Filter is an empty filter ready to use.
+// Filters are unsafe for concurrent use.
+type Filter struct {
+	last uint64
+	ring [ringBlocks]block
 }
 
-type ReplayFilter struct {
-	counter   uint64
-	backtrack [BacktrackWords]uintptr
+// Reset resets the filter to empty state.
+func (f *Filter) Reset() {
+	f.last = 0
+	f.ring[0] = 0
 }
 
-func (filter *ReplayFilter) Init() {
-	filter.counter = 0
-	filter.backtrack[0] = 0
-}
-
-func (filter *ReplayFilter) ValidateCounter(counter uint64, limit uint64) bool {
+// ValidateCounter checks if the counter should be accepted.
+// Overlimit counters (>= limit) are always rejected.
+func (f *Filter) ValidateCounter(counter uint64, limit uint64) bool {
 	if counter >= limit {
 		return false
 	}
-
-	indexWord := counter >> CounterRedundantBitsLog
-
-	if counter > filter.counter {
-
-		// move window forward
-
-		current := filter.counter >> CounterRedundantBitsLog
-		diff := minUint64(indexWord-current, BacktrackWords)
-		for i := uint64(1); i <= diff; i++ {
-			filter.backtrack[(current+i)%BacktrackWords] = 0
+	indexBlock := counter >> blockBitLog
+	if counter > f.last { // move window forward
+		current := f.last >> blockBitLog
+		diff := indexBlock - current
+		if diff > ringBlocks {
+			diff = ringBlocks // cap diff to clear the whole ring
 		}
-		filter.counter = counter
-
-	} else if filter.counter-counter > CounterWindowSize {
-
-		// behind current window
-
+		for i := current + 1; i <= current+diff; i++ {
+			f.ring[i&blockMask] = 0
+		}
+		f.last = counter
+	} else if f.last-counter > windowSize { // behind current window
 		return false
 	}
-
-	indexWord %= BacktrackWords
-	indexBit := counter & uint64(CounterRedundantBits-1)
-
 	// check and set bit
-
-	oldValue := filter.backtrack[indexWord]
-	newValue := oldValue | (1 << indexBit)
-	filter.backtrack[indexWord] = newValue
-	return oldValue != newValue
+	indexBlock &= blockMask
+	indexBit := counter & bitMask
+	old := f.ring[indexBlock]
+	new := old | 1<<indexBit
+	f.ring[indexBlock] = new
+	return old != new
 }

replay/replay_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package replay
@@ -14,22 +14,22 @@ import (
  *
  */
 
-const RejectAfterMessages = (1 << 64) - (1 << 4) - 1
+const RejectAfterMessages = 1<<64 - 1<<13 - 1
 
 func TestReplay(t *testing.T) {
-	var filter ReplayFilter
+	var filter Filter
 
-	T_LIM := CounterWindowSize + 1
+	const T_LIM = windowSize + 1
 
 	testNumber := 0
-	T := func(n uint64, v bool) {
+	T := func(n uint64, expected bool) {
 		testNumber++
-		if filter.ValidateCounter(n, RejectAfterMessages) != v {
-			t.Fatal("Test", testNumber, "failed", n, v)
+		if filter.ValidateCounter(n, RejectAfterMessages) != expected {
+			t.Fatal("Test", testNumber, "failed", n, expected)
 		}
 	}
 
-	filter.Init()
+	filter.Reset()
 
 	T(0, true)                      /*  1 */
 	T(1, true)                      /*  2 */
@@ -67,53 +67,53 @@ func TestReplay(t *testing.T) {
 	T(0, false)                     /* 34 */
 
 	t.Log("Bulk test 1")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := uint64(1); i <= CounterWindowSize; i++ {
+	for i := uint64(1); i <= windowSize; i++ {
 		T(i, true)
 	}
 	T(0, true)
 	T(0, false)
 
 	t.Log("Bulk test 2")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := uint64(2); i <= CounterWindowSize+1; i++ {
+	for i := uint64(2); i <= windowSize+1; i++ {
 		T(i, true)
 	}
 	T(1, true)
 	T(0, false)
 
 	t.Log("Bulk test 3")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize + 1; i > 0; i-- {
+	for i := uint64(windowSize + 1); i > 0; i-- {
 		T(i, true)
 	}
 
 	t.Log("Bulk test 4")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize + 2; i > 1; i-- {
+	for i := uint64(windowSize + 2); i > 1; i-- {
 		T(i, true)
 	}
 	T(0, false)
 
 	t.Log("Bulk test 5")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize; i > 0; i-- {
+	for i := uint64(windowSize); i > 0; i-- {
 		T(i, true)
 	}
-	T(CounterWindowSize+1, true)
+	T(windowSize+1, true)
 	T(0, false)
 
 	t.Log("Bulk test 6")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize; i > 0; i-- {
+	for i := uint64(windowSize); i > 0; i-- {
 		T(i, true)
 	}
 	T(0, true)
-	T(CounterWindowSize+1, true)
+	T(windowSize+1, true)
 }

rwcancel/fdset.go

@@ -1,6 +1,8 @@
+// +build !windows
+
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel

rwcancel/rwcancel.go

@@ -1,8 +1,12 @@
+// +build !windows
+
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
+// Package rwcancel implements cancelable read/write operations on
+// a file descriptor.
 package rwcancel
 
 import (
@@ -42,17 +46,7 @@ func NewRWCancel(fd int) (*RWCancel, error) {
 }
 
 func RetryAfterError(err error) bool {
-	if pe, ok := err.(*os.PathError); ok {
-		err = pe.Err
-	}
-	if errno, ok := err.(syscall.Errno); ok {
-		switch errno {
-		case syscall.EAGAIN, syscall.EINTR:
-			return true
-		}
-
-	}
-	return false
+	return errors.Is(err, syscall.EAGAIN) || errors.Is(err, syscall.EINTR)
 }
 
 func (rw *RWCancel) ReadyRead() bool {
@@ -60,7 +54,13 @@ func (rw *RWCancel) ReadyRead() bool {
 	fdset := fdSet{}
 	fdset.set(rw.fd)
 	fdset.set(closeFd)
-	err := unixSelect(max(rw.fd, closeFd)+1, &fdset.FdSet, nil, nil, nil)
+	var err error
+	for {
+		err = unixSelect(max(rw.fd, closeFd)+1, &fdset.FdSet, nil, nil, nil)
+		if err == nil || !RetryAfterError(err) {
+			break
+		}
+	}
 	if err != nil {
 		return false
 	}
@@ -75,7 +75,13 @@ func (rw *RWCancel) ReadyWrite() bool {
 	fdset := fdSet{}
 	fdset.set(rw.fd)
 	fdset.set(closeFd)
-	err := unixSelect(max(rw.fd, closeFd)+1, nil, &fdset.FdSet, nil, nil)
+	var err error
+	for {
+		err = unixSelect(max(rw.fd, closeFd)+1, nil, &fdset.FdSet, nil, nil)
+		if err == nil || !RetryAfterError(err) {
+			break
+		}
+	}
 	if err != nil {
 		return false
 	}
@@ -113,3 +119,8 @@ func (rw *RWCancel) Cancel() (err error) {
 	_, err = rw.closingWriter.Write([]byte{0})
 	return
 }
+
+func (rw *RWCancel) Close() {
+	rw.closingReader.Close()
+	rw.closingWriter.Close()
+}

rwcancel/rwcancel_windows.go

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: MIT
+
+package rwcancel
+
+type RWCancel struct {
+}
+
+func (*RWCancel) Cancel() {}

rwcancel/select_default.go

@@ -1,8 +1,8 @@
-// +build !linux
+// +build !linux,!windows
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel
@@ -10,5 +10,6 @@ package rwcancel
 import "golang.org/x/sys/unix"
 
 func unixSelect(nfd int, r *unix.FdSet, w *unix.FdSet, e *unix.FdSet, timeout *unix.Timeval) error {
-	return unix.Select(nfd, r, w, e, timeout)
+	_, err := unix.Select(nfd, r, w, e, timeout)
+	return err
 }

rwcancel/select_linux.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel

tai64n/tai64n.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tai64n
@@ -17,16 +17,23 @@ const whitenerMask = uint32(0x1000000 - 1)
 
 type Timestamp [TimestampSize]byte
 
-func Now() Timestamp {
+func stamp(t time.Time) Timestamp {
 	var tai64n Timestamp
-	now := time.Now()
-	secs := base + uint64(now.Unix())
-	nano := uint32(now.Nanosecond()) &^ whitenerMask
+	secs := base + uint64(t.Unix())
+	nano := uint32(t.Nanosecond()) &^ whitenerMask
 	binary.BigEndian.PutUint64(tai64n[:], secs)
 	binary.BigEndian.PutUint32(tai64n[8:], nano)
 	return tai64n
 }
 
+func Now() Timestamp {
+	return stamp(time.Now())
+}
+
 func (t1 Timestamp) After(t2 Timestamp) bool {
 	return bytes.Compare(t1[:], t2[:]) > 0
 }
+
+func (t Timestamp) String() string {
+	return time.Unix(int64(binary.BigEndian.Uint64(t[:8])-base), int64(binary.BigEndian.Uint32(t[8:12]))).String()
+}

tai64n/tai64n_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tai64n
@@ -10,17 +10,31 @@ import (
 	"time"
 )
 
-/* Testing the essential property of the timestamp
- * as used by WireGuard.
- */
+// Test that timestamps are monotonic as required by Wireguard and that
+// nanosecond-level information is whitened to prevent side channel attacks.
 func TestMonotonic(t *testing.T) {
-	old := Now()
-	for i := 0; i < 10000; i++ {
-		time.Sleep(time.Nanosecond)
-		next := Now()
-		if !next.After(old) {
-			t.Error("TAI64N, not monotonically increasing on nano-second scale")
+	startTime := time.Unix(0, 123456789) // a nontrivial bit pattern
+	// Whitening should reduce timestamp granularity
+	// to more than 10 but fewer than 20 milliseconds.
+	tests := []struct {
+		name      string
+		t1, t2    time.Time
+		wantAfter bool
+	}{
+		{"after_10_ns", startTime, startTime.Add(10 * time.Nanosecond), false},
+		{"after_10_us", startTime, startTime.Add(10 * time.Microsecond), false},
+		{"after_1_ms", startTime, startTime.Add(time.Millisecond), false},
+		{"after_10_ms", startTime, startTime.Add(10 * time.Millisecond), false},
+		{"after_20_ms", startTime, startTime.Add(20 * time.Millisecond), true},
 	}
-		old = next
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ts1, ts2 := stamp(tt.t1), stamp(tt.t2)
+			got := ts2.After(ts1)
+			if got != tt.wantAfter {
+				t.Errorf("after = %v; want %v", got, tt.wantAfter)
+			}
+		})
 	}
 }

tests/netns.sh

@@ -36,7 +36,7 @@ netns0="wg-test-$$-0"
 netns1="wg-test-$$-1"
 netns2="wg-test-$$-2"
 program=$1
-export LOG_LEVEL="info"
+export LOG_LEVEL="verbose"
 
 pretty() { echo -e "\x1b[32m\x1b[1m[+] ${1:+NS$1: }${2}\x1b[0m" >&3; }
 pp() { pretty "" "$*"; "$@"; }

tun/helper_test.go

@@ -1,93 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package tun
-
-import (
-	"bytes"
-	"errors"
-	"os"
-	"testing"
-
-	"golang.zx2c4.com/wireguard/tun"
-)
-
-/* Helpers for writing unit tests
- */
-
-type DummyTUN struct {
-	name    string
-	mtu     int
-	packets chan []byte
-	events  chan tun.TUNEvent
-}
-
-func (tun *DummyTUN) File() *os.File {
-	return nil
-}
-
-func (tun *DummyTUN) Name() (string, error) {
-	return tun.name, nil
-}
-
-func (tun *DummyTUN) MTU() (int, error) {
-	return tun.mtu, nil
-}
-
-func (tun *DummyTUN) Write(d []byte, offset int) (int, error) {
-	tun.packets <- d[offset:]
-	return len(d), nil
-}
-
-func (tun *DummyTUN) Close() error {
-	close(tun.events)
-	close(tun.packets)
-	return nil
-}
-
-func (tun *DummyTUN) Events() chan tun.TUNEvent {
-	return tun.events
-}
-
-func (tun *DummyTUN) Read(d []byte, offset int) (int, error) {
-	t, ok := <-tun.packets
-	if !ok {
-		return 0, errors.New("device closed")
-	}
-	copy(d[offset:], t)
-	return len(t), nil
-}
-
-func CreateDummyTUN(name string) (tun.TUNDevice, error) {
-	var dummy DummyTUN
-	dummy.mtu = 0
-	dummy.packets = make(chan []byte, 100)
-	dummy.events = make(chan tun.TUNEvent, 10)
-	return &dummy, nil
-}
-
-func assertNil(t *testing.T, err error) {
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
-func assertEqual(t *testing.T, a []byte, b []byte) {
-	if bytes.Compare(a, b) != 0 {
-		t.Fatal(a, "!=", b)
-	}
-}
-
-func randDevice(t *testing.T) *Device {
-	sk, err := newPrivateKey()
-	if err != nil {
-		t.Fatal(err)
-	}
-	tun, _ := CreateDummyTUN("dummy")
-	logger := NewLogger(LogLevelError, "")
-	device := NewDevice(tun, logger)
-	device.SetPrivateKey(sk)
-	return device
-}

tun/netstack/examples/http_client.go

@@ -0,0 +1,53 @@
+// +build ignore
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"io"
+	"log"
+	"net"
+	"net/http"
+
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+)
+
+func main() {
+	tun, tnet, err := netstack.CreateNetTUN(
+		[]net.IP{net.ParseIP("192.168.4.29")},
+		[]net.IP{net.ParseIP("8.8.8.8")},
+		1420)
+	if err != nil {
+		log.Panic(err)
+	}
+	dev := device.NewDevice(tun, &device.Logger{log.Default(), log.Default(), log.Default()})
+	dev.IpcSet(`private_key=a8dac1d8a70a751f0f699fb14ba1cff7b79cf4fbd8f09f44c6e6a90d0369604f
+public_key=25123c5dcd3328ff645e4f2a3fce0d754400d3887a0cb7c56f0267e20fbf3c5b
+endpoint=163.172.161.0:12912
+allowed_ip=0.0.0.0/0
+`)
+	err = dev.Up()
+	if err != nil {
+		log.Panic(err)
+	}
+
+	client := http.Client{
+		Transport: &http.Transport{
+			DialContext: tnet.DialContext,
+		},
+	}
+	resp, err := client.Get("https://www.zx2c4.com/ip")
+	if err != nil {
+		log.Panic(err)
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Panic(err)
+	}
+	log.Println(string(body))
+}

tun/netstack/examples/http_server.go

@@ -0,0 +1,48 @@
+// +build ignore
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+	"io"
+	"log"
+	"net"
+	"net/http"
+)
+
+func main() {
+	tun, tnet, err := netstack.CreateNetTUN(
+		[]net.IP{net.ParseIP("192.168.4.29")},
+		[]net.IP{net.ParseIP("8.8.8.8"), net.ParseIP("8.8.4.4")},
+		1420,
+	)
+	if err != nil {
+		log.Panic(err)
+	}
+	dev := device.NewDevice(tun, &device.Logger{log.Default(), log.Default(), log.Default()})
+	dev.IpcSet(`private_key=a8dac1d8a70a751f0f699fb14ba1cff7b79cf4fbd8f09f44c6e6a90d0369604f
+public_key=25123c5dcd3328ff645e4f2a3fce0d754400d3887a0cb7c56f0267e20fbf3c5b
+endpoint=163.172.161.0:12912
+allowed_ip=0.0.0.0/0
+persistent_keepalive_interval=25
+    `)
+	dev.Up()
+	listener, err := tnet.ListenTCP(&net.TCPAddr{Port: 80})
+	if err != nil {
+		log.Panicln(err)
+	}
+	http.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
+		log.Printf("> %s - %s - %s", request.RemoteAddr, request.URL.String(), request.UserAgent())
+		io.WriteString(writer, "Hello from userspace TCP!")
+	})
+	err = http.Serve(listener, nil)
+	if err != nil {
+		log.Panicln(err)
+	}
+}

tun/netstack/go.mod

@@ -0,0 +1,9 @@
+module golang.zx2c4.com/wireguard/tun/netstack
+
+go 1.15
+
+require (
+	golang.org/x/net v0.0.0-20201110031124-69a78807bb2b
+	golang.zx2c4.com/wireguard v0.0.20201118
+	gvisor.dev/gvisor v0.0.0-20210109011639-2fb7a49fea98
+)

tun/netstack/go.sum

@@ -0,0 +1,391 @@
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+cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
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+cloud.google.com/go v0.44.2/go.mod h1:60680Gw3Yr4ikxnPRS/oxxkBccT6SA1yMk63TGekxKY=
+cloud.google.com/go v0.45.1/go.mod h1:RpBamKRgapWJb87xiFSdk4g1CME7QZg3uwTez+TSTjc=
+cloud.google.com/go v0.46.3/go.mod h1:a6bKKbmY7er1mI7TEI4lsAkts/mkhTSZK8w33B4RAg0=
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+cloud.google.com/go/bigquery v1.0.1/go.mod h1:i/xbL2UlR5RvWAURpBYZTtm/cXjCha9lbfbpx4poX+o=
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tun/netstack/tun.go

@@ -0,0 +1,818 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package netstack
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"golang.zx2c4.com/wireguard/tun"
+
+	"golang.org/x/net/dns/dnsmessage"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
+)
+
+type netTun struct {
+	stack          *stack.Stack
+	dispatcher     stack.NetworkDispatcher
+	events         chan tun.Event
+	incomingPacket chan buffer.VectorisedView
+	mtu            int
+	dnsServers     []net.IP
+	hasV4, hasV6   bool
+}
+type endpoint netTun
+type Net netTun
+
+func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	e.dispatcher = dispatcher
+}
+
+func (e *endpoint) IsAttached() bool {
+	return e.dispatcher != nil
+}
+
+func (e *endpoint) MTU() uint32 {
+	mtu, err := (*netTun)(e).MTU()
+	if err != nil {
+		panic(err)
+	}
+	return uint32(mtu)
+}
+
+func (*endpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return stack.CapabilityNone
+}
+
+func (*endpoint) MaxHeaderLength() uint16 {
+	return 0
+}
+
+func (*endpoint) LinkAddress() tcpip.LinkAddress {
+	return ""
+}
+
+func (*endpoint) Wait() {}
+
+func (e *endpoint) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
+	e.incomingPacket <- buffer.NewVectorisedView(pkt.Size(), pkt.Views())
+	return nil
+}
+
+func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, stack.PacketBufferList, tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+	panic("not implemented")
+}
+
+func (*endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareNone
+}
+
+func (e *endpoint) AddHeader(local, remote tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+}
+
+func CreateNetTUN(localAddresses []net.IP, dnsServers []net.IP, mtu int) (tun.Device, *Net, error) {
+	opts := stack.Options{
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol, udp.NewProtocol},
+		HandleLocal:        true,
+	}
+	dev := &netTun{
+		stack:          stack.New(opts),
+		events:         make(chan tun.Event, 10),
+		incomingPacket: make(chan buffer.VectorisedView),
+		dnsServers:     dnsServers,
+		mtu:            mtu,
+	}
+	tcpipErr := dev.stack.CreateNIC(1, (*endpoint)(dev))
+	if tcpipErr != nil {
+		return nil, nil, fmt.Errorf("CreateNIC: %v", tcpipErr)
+	}
+	for _, ip := range localAddresses {
+		if ip4 := ip.To4(); ip4 != nil {
+			tcpipErr = dev.stack.AddAddress(1, ipv4.ProtocolNumber, tcpip.Address(ip4))
+			if tcpipErr != nil {
+				return nil, nil, fmt.Errorf("AddAddress(%v): %v", ip4, tcpipErr)
+			}
+			dev.hasV4 = true
+		} else {
+			tcpipErr = dev.stack.AddAddress(1, ipv6.ProtocolNumber, tcpip.Address(ip))
+			if tcpipErr != nil {
+				return nil, nil, fmt.Errorf("AddAddress(%v): %v", ip4, tcpipErr)
+			}
+			dev.hasV6 = true
+		}
+	}
+	if dev.hasV4 {
+		dev.stack.AddRoute(tcpip.Route{Destination: header.IPv4EmptySubnet, NIC: 1})
+	}
+	if dev.hasV6 {
+		dev.stack.AddRoute(tcpip.Route{Destination: header.IPv6EmptySubnet, NIC: 1})
+	}
+
+	dev.events <- tun.EventUp
+	return dev, (*Net)(dev), nil
+}
+
+func (tun *netTun) Name() (string, error) {
+	return "go", nil
+}
+
+func (tun *netTun) File() *os.File {
+	return nil
+}
+
+func (tun *netTun) Events() chan tun.Event {
+	return tun.events
+}
+
+func (tun *netTun) Read(buf []byte, offset int) (int, error) {
+	view, ok := <-tun.incomingPacket
+	if !ok {
+		return 0, os.ErrClosed
+	}
+	return view.Read(buf[offset:])
+}
+
+func (tun *netTun) Write(buf []byte, offset int) (int, error) {
+	packet := buf[offset:]
+	if len(packet) == 0 {
+		return 0, nil
+	}
+
+	pkb := stack.NewPacketBuffer(stack.PacketBufferOptions{Data: buffer.NewVectorisedView(len(packet), []buffer.View{buffer.NewViewFromBytes(packet)})})
+	switch packet[0] >> 4 {
+	case 4:
+		tun.dispatcher.DeliverNetworkPacket("", "", ipv4.ProtocolNumber, pkb)
+	case 6:
+		tun.dispatcher.DeliverNetworkPacket("", "", ipv6.ProtocolNumber, pkb)
+	}
+
+	return len(buf), nil
+}
+
+func (tun *netTun) Flush() error {
+	return nil
+}
+
+func (tun *netTun) Close() error {
+	tun.stack.RemoveNIC(1)
+
+	if tun.events != nil {
+		close(tun.events)
+	}
+	if tun.incomingPacket != nil {
+		close(tun.incomingPacket)
+	}
+	return nil
+}
+
+func (tun *netTun) MTU() (int, error) {
+	return tun.mtu, nil
+}
+
+func convertToFullAddr(ip net.IP, port int) (tcpip.FullAddress, tcpip.NetworkProtocolNumber) {
+	if ip4 := ip.To4(); ip4 != nil {
+		return tcpip.FullAddress{
+			NIC:  1,
+			Addr: tcpip.Address(ip4),
+			Port: uint16(port),
+		}, ipv4.ProtocolNumber
+	} else {
+		return tcpip.FullAddress{
+			NIC:  1,
+			Addr: tcpip.Address(ip),
+			Port: uint16(port),
+		}, ipv6.ProtocolNumber
+	}
+}
+
+func (net *Net) DialContextTCP(ctx context.Context, addr *net.TCPAddr) (*gonet.TCPConn, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.DialContextTCP(ctx, net.stack, fa, pn)
+}
+
+func (net *Net) DialTCP(addr *net.TCPAddr) (*gonet.TCPConn, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.DialTCP(net.stack, fa, pn)
+}
+
+func (net *Net) ListenTCP(addr *net.TCPAddr) (*gonet.TCPListener, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.ListenTCP(net.stack, fa, pn)
+}
+
+func (net *Net) DialUDP(laddr, raddr *net.UDPAddr) (*gonet.UDPConn, error) {
+	var lfa, rfa *tcpip.FullAddress
+	var pn tcpip.NetworkProtocolNumber
+	if laddr != nil {
+		var addr tcpip.FullAddress
+		addr, pn = convertToFullAddr(laddr.IP, laddr.Port)
+		lfa = &addr
+	}
+	if raddr != nil {
+		var addr tcpip.FullAddress
+		addr, pn = convertToFullAddr(raddr.IP, raddr.Port)
+		rfa = &addr
+	}
+	return gonet.DialUDP(net.stack, lfa, rfa, pn)
+}
+
+var (
+	errNoSuchHost                   = errors.New("no such host")
+	errLameReferral                 = errors.New("lame referral")
+	errCannotUnmarshalDNSMessage    = errors.New("cannot unmarshal DNS message")
+	errCannotMarshalDNSMessage      = errors.New("cannot marshal DNS message")
+	errServerMisbehaving            = errors.New("server misbehaving")
+	errInvalidDNSResponse           = errors.New("invalid DNS response")
+	errNoAnswerFromDNSServer        = errors.New("no answer from DNS server")
+	errServerTemporarilyMisbehaving = errors.New("server misbehaving")
+	errCanceled                     = errors.New("operation was canceled")
+	errTimeout                      = errors.New("i/o timeout")
+	errNumericPort                  = errors.New("port must be numeric")
+	errNoSuitableAddress            = errors.New("no suitable address found")
+	errMissingAddress               = errors.New("missing address")
+)
+
+func (net *Net) LookupHost(host string) (addrs []string, err error) {
+	return net.LookupContextHost(context.Background(), host)
+}
+
+func isDomainName(s string) bool {
+	l := len(s)
+	if l == 0 || l > 254 || l == 254 && s[l-1] != '.' {
+		return false
+	}
+	last := byte('.')
+	nonNumeric := false
+	partlen := 0
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		switch {
+		default:
+			return false
+		case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_':
+			nonNumeric = true
+			partlen++
+		case '0' <= c && c <= '9':
+			partlen++
+		case c == '-':
+			if last == '.' {
+				return false
+			}
+			partlen++
+			nonNumeric = true
+		case c == '.':
+			if last == '.' || last == '-' {
+				return false
+			}
+			if partlen > 63 || partlen == 0 {
+				return false
+			}
+			partlen = 0
+		}
+		last = c
+	}
+	if last == '-' || partlen > 63 {
+		return false
+	}
+	return nonNumeric
+}
+
+func randU16() uint16 {
+	var b [2]byte
+	_, err := rand.Read(b[:])
+	if err != nil {
+		panic(err)
+	}
+	return binary.LittleEndian.Uint16(b[:])
+}
+
+func newRequest(q dnsmessage.Question) (id uint16, udpReq, tcpReq []byte, err error) {
+	id = randU16()
+	b := dnsmessage.NewBuilder(make([]byte, 2, 514), dnsmessage.Header{ID: id, RecursionDesired: true})
+	b.EnableCompression()
+	if err := b.StartQuestions(); err != nil {
+		return 0, nil, nil, err
+	}
+	if err := b.Question(q); err != nil {
+		return 0, nil, nil, err
+	}
+	tcpReq, err = b.Finish()
+	udpReq = tcpReq[2:]
+	l := len(tcpReq) - 2
+	tcpReq[0] = byte(l >> 8)
+	tcpReq[1] = byte(l)
+	return id, udpReq, tcpReq, err
+}
+
+func equalASCIIName(x, y dnsmessage.Name) bool {
+	if x.Length != y.Length {
+		return false
+	}
+	for i := 0; i < int(x.Length); i++ {
+		a := x.Data[i]
+		b := y.Data[i]
+		if 'A' <= a && a <= 'Z' {
+			a += 0x20
+		}
+		if 'A' <= b && b <= 'Z' {
+			b += 0x20
+		}
+		if a != b {
+			return false
+		}
+	}
+	return true
+}
+
+func checkResponse(reqID uint16, reqQues dnsmessage.Question, respHdr dnsmessage.Header, respQues dnsmessage.Question) bool {
+	if !respHdr.Response {
+		return false
+	}
+	if reqID != respHdr.ID {
+		return false
+	}
+	if reqQues.Type != respQues.Type || reqQues.Class != respQues.Class || !equalASCIIName(reqQues.Name, respQues.Name) {
+		return false
+	}
+	return true
+}
+
+func dnsPacketRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
+	if _, err := c.Write(b); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	b = make([]byte, 512)
+	for {
+		n, err := c.Read(b)
+		if err != nil {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		var p dnsmessage.Parser
+		h, err := p.Start(b[:n])
+		if err != nil {
+			continue
+		}
+		q, err := p.Question()
+		if err != nil || !checkResponse(id, query, h, q) {
+			continue
+		}
+		return p, h, nil
+	}
+}
+
+func dnsStreamRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
+	if _, err := c.Write(b); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	b = make([]byte, 1280)
+	if _, err := io.ReadFull(c, b[:2]); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	l := int(b[0])<<8 | int(b[1])
+	if l > len(b) {
+		b = make([]byte, l)
+	}
+	n, err := io.ReadFull(c, b[:l])
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	var p dnsmessage.Parser
+	h, err := p.Start(b[:n])
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
+	}
+	q, err := p.Question()
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
+	}
+	if !checkResponse(id, query, h, q) {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
+	}
+	return p, h, nil
+}
+
+func (tnet *Net) exchange(ctx context.Context, server net.IP, q dnsmessage.Question, timeout time.Duration) (dnsmessage.Parser, dnsmessage.Header, error) {
+	q.Class = dnsmessage.ClassINET
+	id, udpReq, tcpReq, err := newRequest(q)
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotMarshalDNSMessage
+	}
+
+	for _, useUDP := range []bool{true, false} {
+		ctx, cancel := context.WithDeadline(ctx, time.Now().Add(timeout))
+		defer cancel()
+
+		var c net.Conn
+		var err error
+		if useUDP {
+			c, err = tnet.DialUDP(nil, &net.UDPAddr{IP: server, Port: 53})
+		} else {
+			c, err = tnet.DialContextTCP(ctx, &net.TCPAddr{IP: server, Port: 53})
+		}
+
+		if err != nil {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		if d, ok := ctx.Deadline(); ok && !d.IsZero() {
+			c.SetDeadline(d)
+		}
+		var p dnsmessage.Parser
+		var h dnsmessage.Header
+		if useUDP {
+			p, h, err = dnsPacketRoundTrip(c, id, q, udpReq)
+		} else {
+			p, h, err = dnsStreamRoundTrip(c, id, q, tcpReq)
+		}
+		c.Close()
+		if err != nil {
+			if err == context.Canceled {
+				err = errCanceled
+			} else if err == context.DeadlineExceeded {
+				err = errTimeout
+			}
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		if err := p.SkipQuestion(); err != dnsmessage.ErrSectionDone {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
+		}
+		if h.Truncated {
+			continue
+		}
+		return p, h, nil
+	}
+	return dnsmessage.Parser{}, dnsmessage.Header{}, errNoAnswerFromDNSServer
+}
+
+func checkHeader(p *dnsmessage.Parser, h dnsmessage.Header) error {
+	if h.RCode == dnsmessage.RCodeNameError {
+		return errNoSuchHost
+	}
+	_, err := p.AnswerHeader()
+	if err != nil && err != dnsmessage.ErrSectionDone {
+		return errCannotUnmarshalDNSMessage
+	}
+	if h.RCode == dnsmessage.RCodeSuccess && !h.Authoritative && !h.RecursionAvailable && err == dnsmessage.ErrSectionDone {
+		return errLameReferral
+	}
+	if h.RCode != dnsmessage.RCodeSuccess && h.RCode != dnsmessage.RCodeNameError {
+		if h.RCode == dnsmessage.RCodeServerFailure {
+			return errServerTemporarilyMisbehaving
+		}
+		return errServerMisbehaving
+	}
+	return nil
+}
+
+func skipToAnswer(p *dnsmessage.Parser, qtype dnsmessage.Type) error {
+	for {
+		h, err := p.AnswerHeader()
+		if err == dnsmessage.ErrSectionDone {
+			return errNoSuchHost
+		}
+		if err != nil {
+			return errCannotUnmarshalDNSMessage
+		}
+		if h.Type == qtype {
+			return nil
+		}
+		if err := p.SkipAnswer(); err != nil {
+			return errCannotUnmarshalDNSMessage
+		}
+	}
+}
+
+func (tnet *Net) tryOneName(ctx context.Context, name string, qtype dnsmessage.Type) (dnsmessage.Parser, string, error) {
+	var lastErr error
+
+	n, err := dnsmessage.NewName(name)
+	if err != nil {
+		return dnsmessage.Parser{}, "", errCannotMarshalDNSMessage
+	}
+	q := dnsmessage.Question{
+		Name:  n,
+		Type:  qtype,
+		Class: dnsmessage.ClassINET,
+	}
+
+	for i := 0; i < 2; i++ {
+		for _, server := range tnet.dnsServers {
+			p, h, err := tnet.exchange(ctx, server, q, time.Second*5)
+			if err != nil {
+				dnsErr := &net.DNSError{
+					Err:    err.Error(),
+					Name:   name,
+					Server: server.String(),
+				}
+				if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
+					dnsErr.IsTimeout = true
+				}
+				if _, ok := err.(*net.OpError); ok {
+					dnsErr.IsTemporary = true
+				}
+				lastErr = dnsErr
+				continue
+			}
+
+			if err := checkHeader(&p, h); err != nil {
+				dnsErr := &net.DNSError{
+					Err:    err.Error(),
+					Name:   name,
+					Server: server.String(),
+				}
+				if err == errServerTemporarilyMisbehaving {
+					dnsErr.IsTemporary = true
+				}
+				if err == errNoSuchHost {
+					dnsErr.IsNotFound = true
+					return p, server.String(), dnsErr
+				}
+				lastErr = dnsErr
+				continue
+			}
+
+			err = skipToAnswer(&p, qtype)
+			if err == nil {
+				return p, server.String(), nil
+			}
+			lastErr = &net.DNSError{
+				Err:    err.Error(),
+				Name:   name,
+				Server: server.String(),
+			}
+			if err == errNoSuchHost {
+				lastErr.(*net.DNSError).IsNotFound = true
+				return p, server.String(), lastErr
+			}
+		}
+	}
+	return dnsmessage.Parser{}, "", lastErr
+}
+
+func (tnet *Net) LookupContextHost(ctx context.Context, host string) ([]string, error) {
+	if host == "" || (!tnet.hasV6 && !tnet.hasV4) {
+		return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
+	}
+	zlen := len(host)
+	if strings.IndexByte(host, ':') != -1 {
+		if zidx := strings.LastIndexByte(host, '%'); zidx != -1 {
+			zlen = zidx
+		}
+	}
+	if ip := net.ParseIP(host[:zlen]); ip != nil {
+		return []string{host[:zlen]}, nil
+	}
+
+	if !isDomainName(host) {
+		return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
+	}
+	type result struct {
+		p      dnsmessage.Parser
+		server string
+		error
+	}
+	var addrsV4, addrsV6 []net.IP
+	lanes := 0
+	if tnet.hasV4 {
+		lanes++
+	}
+	if tnet.hasV6 {
+		lanes++
+	}
+	lane := make(chan result, lanes)
+	var lastErr error
+	if tnet.hasV4 {
+		go func() {
+			p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeA)
+			lane <- result{p, server, err}
+		}()
+	}
+	if tnet.hasV6 {
+		go func() {
+			p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeAAAA)
+			lane <- result{p, server, err}
+		}()
+	}
+	for l := 0; l < lanes; l++ {
+		result := <-lane
+		if result.error != nil {
+			if lastErr == nil {
+				lastErr = result.error
+			}
+			continue
+		}
+
+	loop:
+		for {
+			h, err := result.p.AnswerHeader()
+			if err != nil && err != dnsmessage.ErrSectionDone {
+				lastErr = &net.DNSError{
+					Err:    errCannotMarshalDNSMessage.Error(),
+					Name:   host,
+					Server: result.server,
+				}
+			}
+			if err != nil {
+				break
+			}
+			switch h.Type {
+			case dnsmessage.TypeA:
+				a, err := result.p.AResource()
+				if err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				addrsV4 = append(addrsV4, net.IP(a.A[:]))
+
+			case dnsmessage.TypeAAAA:
+				aaaa, err := result.p.AAAAResource()
+				if err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				addrsV6 = append(addrsV6, net.IP(aaaa.AAAA[:]))
+
+			default:
+				if err := result.p.SkipAnswer(); err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				continue
+			}
+		}
+	}
+	// We don't do RFC6724. Instead just put V6 addresess first if an IPv6 address is enabled
+	var addrs []net.IP
+	if tnet.hasV6 {
+		addrs = append(addrsV6, addrsV4...)
+	} else {
+		addrs = append(addrsV4, addrsV6...)
+	}
+
+	if len(addrs) == 0 && lastErr != nil {
+		return nil, lastErr
+	}
+	saddrs := make([]string, 0, len(addrs))
+	for _, ip := range addrs {
+		saddrs = append(saddrs, ip.String())
+	}
+	return saddrs, nil
+}
+
+func partialDeadline(now, deadline time.Time, addrsRemaining int) (time.Time, error) {
+	if deadline.IsZero() {
+		return deadline, nil
+	}
+	timeRemaining := deadline.Sub(now)
+	if timeRemaining <= 0 {
+		return time.Time{}, errTimeout
+	}
+	timeout := timeRemaining / time.Duration(addrsRemaining)
+	const saneMinimum = 2 * time.Second
+	if timeout < saneMinimum {
+		if timeRemaining < saneMinimum {
+			timeout = timeRemaining
+		} else {
+			timeout = saneMinimum
+		}
+	}
+	return now.Add(timeout), nil
+}
+
+func (tnet *Net) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
+	var acceptV4, acceptV6, useUDP bool
+	if len(network) == 3 {
+		acceptV4 = true
+		acceptV6 = true
+	} else if len(network) == 4 {
+		acceptV4 = network[3] == '4'
+		acceptV6 = network[3] == '6'
+	}
+	if !acceptV4 && !acceptV6 {
+		return nil, &net.OpError{Op: "dial", Err: net.UnknownNetworkError(network)}
+	}
+	if network[:3] == "udp" {
+		useUDP = true
+	} else if network[:3] != "tcp" {
+		return nil, &net.OpError{Op: "dial", Err: net.UnknownNetworkError(network)}
+	}
+	host, sport, err := net.SplitHostPort(address)
+	if err != nil {
+		return nil, &net.OpError{Op: "dial", Err: err}
+	}
+	port, err := strconv.Atoi(sport)
+	if err != nil || port < 0 || port > 65535 {
+		return nil, &net.OpError{Op: "dial", Err: errNumericPort}
+	}
+	allAddr, err := tnet.LookupContextHost(ctx, host)
+	if err != nil {
+		return nil, &net.OpError{Op: "dial", Err: err}
+	}
+	var addrs []net.IP
+	for _, addr := range allAddr {
+		if strings.IndexByte(addr, ':') != -1 && acceptV6 {
+			addrs = append(addrs, net.ParseIP(addr))
+		} else if strings.IndexByte(addr, '.') != -1 && acceptV4 {
+			addrs = append(addrs, net.ParseIP(addr))
+		}
+	}
+	if len(addrs) == 0 && len(allAddr) != 0 {
+		return nil, &net.OpError{Op: "dial", Err: errNoSuitableAddress}
+	}
+
+	var firstErr error
+	for i, addr := range addrs {
+		select {
+		case <-ctx.Done():
+			err := ctx.Err()
+			if err == context.Canceled {
+				err = errCanceled
+			} else if err == context.DeadlineExceeded {
+				err = errTimeout
+			}
+			return nil, &net.OpError{Op: "dial", Err: err}
+		default:
+		}
+
+		dialCtx := ctx
+		if deadline, hasDeadline := ctx.Deadline(); hasDeadline {
+			partialDeadline, err := partialDeadline(time.Now(), deadline, len(addrs)-i)
+			if err != nil {
+				if firstErr == nil {
+					firstErr = &net.OpError{Op: "dial", Err: err}
+				}
+				break
+			}
+			if partialDeadline.Before(deadline) {
+				var cancel context.CancelFunc
+				dialCtx, cancel = context.WithDeadline(ctx, partialDeadline)
+				defer cancel()
+			}
+		}
+
+		var c net.Conn
+		if useUDP {
+			c, err = tnet.DialUDP(nil, &net.UDPAddr{IP: addr, Port: port})
+		} else {
+			c, err = tnet.DialContextTCP(dialCtx, &net.TCPAddr{IP: addr, Port: port})
+		}
+		if err == nil {
+			return c, nil
+		}
+		if firstErr == nil {
+			firstErr = err
+		}
+	}
+	if firstErr == nil {
+		firstErr = &net.OpError{Op: "dial", Err: errMissingAddress}
+	}
+	return nil, firstErr
+}
+
+func (tnet *Net) Dial(network, address string) (net.Conn, error) {
+	return tnet.DialContext(context.Background(), network, address)
+}

tun/operateonfd.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun

tun/tun.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -9,21 +9,21 @@ import (
 	"os"
 )
 
-type TUNEvent int
+type Event int
 
 const (
-	TUNEventUp = 1 << iota
-	TUNEventDown
-	TUNEventMTUUpdate
+	EventUp = 1 << iota
+	EventDown
+	EventMTUUpdate
 )
 
-type TUNDevice interface {
+type Device interface {
 	File() *os.File                 // returns the file descriptor of the device
 	Read([]byte, int) (int, error)  // read a packet from the device (without any additional headers)
 	Write([]byte, int) (int, error) // writes a packet to the device (without any additional headers)
 	Flush() error                   // flush all previous writes to the device
 	MTU() (int, error)              // returns the MTU of the device
 	Name() (string, error)          // fetches and returns the current name
-	Events() chan TUNEvent          // returns a constant channel of events related to the device
+	Events() chan Event             // returns a constant channel of events related to the device
 	Close() error                   // stops the device and closes the event channel
 }

tun/tun_darwin.go

@@ -1,16 +1,18 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
 	"os"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"golang.org/x/net/ipv6"
@@ -19,28 +21,25 @@ import (
 
 const utunControlName = "com.apple.net.utun_control"
 
-// _CTLIOCGINFO value derived from /usr/include/sys/{kern_control,ioccom}.h
-const _CTLIOCGINFO = (0x40000000 | 0x80000000) | ((100 & 0x1fff) << 16) | uint32(byte('N'))<<8 | 3
-
-// sockaddr_ctl specifeid in /usr/include/sys/kern_control.h
-type sockaddrCtl struct {
-	scLen      uint8
-	scFamily   uint8
-	ssSysaddr  uint16
-	scID       uint32
-	scUnit     uint32
-	scReserved [5]uint32
-}
-
 type NativeTun struct {
 	name        string
 	tunFile     *os.File
-	events      chan TUNEvent
+	events      chan Event
 	errors      chan error
 	routeSocket int
 }
 
-var sockaddrCtlSize uintptr = 32
+func retryInterfaceByIndex(index int) (iface *net.Interface, err error) {
+	for i := 0; i < 20; i++ {
+		iface, err = net.InterfaceByIndex(index)
+		if err != nil && errors.Is(err, syscall.ENOMEM) {
+			time.Sleep(time.Duration(i) * time.Second / 3)
+			continue
+		}
+		return iface, err
+	}
+	return nil, err
+}
 
 func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 	var (
@@ -48,10 +47,7 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 		statusMTU int
 	)
 
-	defer func() {
-		close(tun.events)
-		tun.routeSocket = -1
-	}()
+	defer close(tun.events)
 
 	data := make([]byte, os.Getpagesize())
 	for {
@@ -77,7 +73,7 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 			continue
 		}
 
-		iface, err := net.InterfaceByIndex(ifindex)
+		iface, err := retryInterfaceByIndex(ifindex)
 		if err != nil {
 			tun.errors <- err
 			return
@@ -86,22 +82,22 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 		// Up / Down event
 		up := (iface.Flags & net.FlagUp) != 0
 		if up != statusUp && up {
-			tun.events <- TUNEventUp
+			tun.events <- EventUp
 		}
 		if up != statusUp && !up {
-			tun.events <- TUNEventDown
+			tun.events <- EventDown
 		}
 		statusUp = up
 
 		// MTU changes
 		if iface.MTU != statusMTU {
-			tun.events <- TUNEventMTUUpdate
+			tun.events <- EventMTUUpdate
 		}
 		statusMTU = iface.MTU
 	}
 }
 
-func CreateTUN(name string, mtu int) (TUNDevice, error) {
+func CreateTUN(name string, mtu int) (Device, error) {
 	ifIndex := -1
 	if name != "utun" {
 		_, err := fmt.Sscanf(name, "utun%d", &ifIndex)
@@ -116,43 +112,21 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 		return nil, err
 	}
 
-	var ctlInfo = &struct {
-		ctlID   uint32
-		ctlName [96]byte
-	}{}
-
-	copy(ctlInfo.ctlName[:], []byte(utunControlName))
-
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(_CTLIOCGINFO),
-		uintptr(unsafe.Pointer(ctlInfo)),
-	)
-
-	if errno != 0 {
-		return nil, fmt.Errorf("_CTLIOCGINFO: %v", errno)
+	ctlInfo := &unix.CtlInfo{}
+	copy(ctlInfo.Name[:], []byte(utunControlName))
+	err = unix.IoctlCtlInfo(fd, ctlInfo)
+	if err != nil {
+		return nil, fmt.Errorf("IoctlGetCtlInfo: %w", err)
 	}
 
-	sc := sockaddrCtl{
-		scLen:     uint8(sockaddrCtlSize),
-		scFamily:  unix.AF_SYSTEM,
-		ssSysaddr: 2,
-		scID:      ctlInfo.ctlID,
-		scUnit:    uint32(ifIndex) + 1,
+	sc := &unix.SockaddrCtl{
+		ID:   ctlInfo.Id,
+		Unit: uint32(ifIndex) + 1,
 	}
 
-	scPointer := unsafe.Pointer(&sc)
-
-	_, _, errno = unix.RawSyscall(
-		unix.SYS_CONNECT,
-		uintptr(fd),
-		uintptr(scPointer),
-		uintptr(sockaddrCtlSize),
-	)
-
-	if errno != 0 {
-		return nil, fmt.Errorf("SYS_CONNECT: %v", errno)
+	err = unix.Connect(fd, sc)
+	if err != nil {
+		return nil, err
 	}
 
 	err = syscall.SetNonblock(fd, true)
@@ -171,10 +145,10 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	return tun, err
 }
 
-func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
+func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 	tun := &NativeTun{
 		tunFile: file,
-		events:  make(chan TUNEvent, 10),
+		events:  make(chan Event, 10),
 		errors:  make(chan error, 5),
 	}
 
@@ -216,27 +190,19 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 }
 
 func (tun *NativeTun) Name() (string, error) {
-	var ifName struct {
-		name [16]byte
-	}
-	ifNameSize := uintptr(16)
-
-	var errno syscall.Errno
+	var err error
 	tun.operateOnFd(func(fd uintptr) {
-		_, _, errno = unix.Syscall6(
-			unix.SYS_GETSOCKOPT,
-			fd,
+		tun.name, err = unix.GetsockoptString(
+			int(fd),
 			2, /* #define SYSPROTO_CONTROL 2 */
 			2, /* #define UTUN_OPT_IFNAME 2 */
-			uintptr(unsafe.Pointer(&ifName)),
-			uintptr(unsafe.Pointer(&ifNameSize)), 0)
+		)
 	})
 
-	if errno != 0 {
-		return "", fmt.Errorf("SYS_GETSOCKOPT: %v", errno)
+	if err != nil {
+		return "", fmt.Errorf("GetSockoptString: %w", err)
 	}
 
-	tun.name = string(ifName.name[:ifNameSize-1])
 	return tun.name, nil
 }
 
@@ -244,7 +210,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan TUNEvent {
+func (tun *NativeTun) Events() chan Event {
 	return tun.events
 }
 
@@ -286,7 +252,7 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 }
 
 func (tun *NativeTun) Flush() error {
-	//TODO: can flushing be implemented by buffering and using sendmmsg?
+	// TODO: can flushing be implemented by buffering and using sendmmsg?
 	return nil
 }
 
@@ -306,11 +272,6 @@ func (tun *NativeTun) Close() error {
 }
 
 func (tun *NativeTun) setMTU(n int) error {
-
-	// open datagram socket
-
-	var fd int
-
 	fd, err := unix.Socket(
 		unix.AF_INET,
 		unix.SOCK_DGRAM,
@@ -323,29 +284,18 @@ func (tun *NativeTun) setMTU(n int) error {
 
 	defer unix.Close(fd)
 
-	// do ioctl call
-
-	var ifr [32]byte
-	copy(ifr[:], tun.name)
-	*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCSIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-
-	if errno != 0 {
-		return fmt.Errorf("failed to set MTU on %s", tun.name)
+	var ifr unix.IfreqMTU
+	copy(ifr.Name[:], tun.name)
+	ifr.MTU = int32(n)
+	err = unix.IoctlSetIfreqMTU(fd, &ifr)
+	if err != nil {
+		return fmt.Errorf("failed to set MTU on %s: %w", tun.name, err)
 	}
 
 	return nil
 }
 
 func (tun *NativeTun) MTU() (int, error) {
-
-	// open datagram socket
-
 	fd, err := unix.Socket(
 		unix.AF_INET,
 		unix.SOCK_DGRAM,
@@ -358,19 +308,10 @@ func (tun *NativeTun) MTU() (int, error) {
 
 	defer unix.Close(fd)
 
-	// do ioctl call
-
-	var ifr [64]byte
-	copy(ifr[:], tun.name)
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCGIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-	if errno != 0 {
-		return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
+	ifr, err := unix.IoctlGetIfreqMTU(fd, tun.name)
+	if err != nil {
+		return 0, fmt.Errorf("failed to get MTU on %s: %w", tun.name, err)
 	}
 
-	return int(*(*int32)(unsafe.Pointer(&ifr[16]))), nil
+	return int(ifr.MTU), nil
 }

tun/tun_freebsd.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -26,7 +26,7 @@ const (
 	_TUNSIFPID  = 0x2000745f
 )
 
-//TODO: move into x/sys/unix
+// TODO: move into x/sys/unix
 const (
 	SIOCGIFINFO_IN6        = 0xc048696c
 	SIOCSIFINFO_IN6        = 0xc048696d
@@ -79,7 +79,7 @@ type in6_ndireq struct {
 type NativeTun struct {
 	name        string
 	tunFile     *os.File
-	events      chan TUNEvent
+	events      chan Event
 	errors      chan error
 	routeSocket int
 }
@@ -125,16 +125,16 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 		// Up / Down event
 		up := (iface.Flags & net.FlagUp) != 0
 		if up != statusUp && up {
-			tun.events <- TUNEventUp
+			tun.events <- EventUp
 		}
 		if up != statusUp && !up {
-			tun.events <- TUNEventDown
+			tun.events <- EventDown
 		}
 		statusUp = up
 
 		// MTU changes
 		if iface.MTU != statusMTU {
-			tun.events <- TUNEventMTUUpdate
+			tun.events <- EventMTUUpdate
 		}
 		statusMTU = iface.MTU
 	}
@@ -246,7 +246,7 @@ func tunDestroy(name string) error {
 	return nil
 }
 
-func CreateTUN(name string, mtu int) (TUNDevice, error) {
+func CreateTUN(name string, mtu int) (Device, error) {
 	if len(name) > unix.IFNAMSIZ-1 {
 		return nil, errors.New("interface name too long")
 	}
@@ -287,7 +287,7 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to put into IFHEAD mode: %v", errno)
+		return nil, fmt.Errorf("Unable to put into IFHEAD mode: %w", errno)
 	}
 
 	// Open control sockets
@@ -328,7 +328,7 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to get nd6 flags for %s: %v", assignedName, errno)
+		return nil, fmt.Errorf("Unable to get nd6 flags for %s: %w", assignedName, errno)
 	}
 	ndireq.Flags = ndireq.Flags &^ ND6_IFF_AUTO_LINKLOCAL
 	ndireq.Flags = ndireq.Flags | ND6_IFF_NO_DAD
@@ -341,7 +341,7 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to set nd6 flags for %s: %v", assignedName, errno)
+		return nil, fmt.Errorf("Unable to set nd6 flags for %s: %w", assignedName, errno)
 	}
 
 	// Rename the interface
@@ -359,17 +359,17 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Failed to rename %s to %s: %v", assignedName, name, errno)
+		return nil, fmt.Errorf("Failed to rename %s to %s: %w", assignedName, name, errno)
 	}
 
 	return CreateTUNFromFile(tunFile, mtu)
 }
 
-func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
+func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 
 	tun := &NativeTun{
 		tunFile: file,
-		events:  make(chan TUNEvent, 10),
+		events:  make(chan Event, 10),
 		errors:  make(chan error, 1),
 	}
 
@@ -425,7 +425,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan TUNEvent {
+func (tun *NativeTun) Events() chan Event {
 	return tun.events
 }
 
@@ -467,7 +467,7 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 }
 
 func (tun *NativeTun) Flush() error {
-	//TODO: can flushing be implemented by buffering and using sendmmsg?
+	// TODO: can flushing be implemented by buffering and using sendmmsg?
 	return nil
 }
 

tun/tun_linux.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -10,9 +10,7 @@ package tun
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
-	"net"
 	"os"
 	"sync"
 	"syscall"
@@ -21,6 +19,7 @@ import (
 
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
+
 	"golang.zx2c4.com/wireguard/rwcancel"
 )
 
@@ -32,14 +31,17 @@ const (
 type NativeTun struct {
 	tunFile                 *os.File
 	index                   int32      // if index
-	name                    string        // name of interface
 	errors                  chan error // async error handling
-	events                  chan TUNEvent // device related events
-	nopi                    bool          // the device was pased IFF_NO_PI
+	events                  chan Event // device related events
+	nopi                    bool       // the device was passed IFF_NO_PI
 	netlinkSock             int
 	netlinkCancel           *rwcancel.RWCancel
 	hackListenerClosed      sync.Mutex
 	statusListenersShutdown chan struct{}
+
+	nameOnce  sync.Once // guards calling initNameCache, which sets following fields
+	nameCache string    // name of interface
+	nameErr   error
 }
 
 func (tun *NativeTun) File() *os.File {
@@ -64,14 +66,19 @@ func (tun *NativeTun) routineHackListener() {
 		}
 		switch err {
 		case unix.EINVAL:
-			tun.events <- TUNEventUp
+			// If the tunnel is up, it reports that write() is
+			// allowed but we provided invalid data.
+			tun.events <- EventUp
 		case unix.EIO:
-			tun.events <- TUNEventDown
+			// If the tunnel is down, it reports that no I/O
+			// is possible, without checking our provided data.
+			tun.events <- EventDown
 		default:
 			return
 		}
 		select {
 		case <-time.After(time.Second):
+			// nothing
 		case <-tun.statusListenersShutdown:
 			return
 		}
@@ -85,7 +92,7 @@ func createNetlinkSocket() (int, error) {
 	}
 	saddr := &unix.SockaddrNetlink{
 		Family: unix.AF_NETLINK,
-		Groups: uint32((1 << (unix.RTNLGRP_LINK - 1)) | (1 << (unix.RTNLGRP_IPV4_IFADDR - 1)) | (1 << (unix.RTNLGRP_IPV6_IFADDR - 1))),
+		Groups: unix.RTMGRP_LINK | unix.RTMGRP_IPV4_IFADDR | unix.RTMGRP_IPV6_IFADDR,
 	}
 	err = unix.Bind(sock, saddr)
 	if err != nil {
@@ -99,10 +106,10 @@ func (tun *NativeTun) routineNetlinkListener() {
 		unix.Close(tun.netlinkSock)
 		tun.hackListenerClosed.Lock()
 		close(tun.events)
+		tun.netlinkCancel.Close()
 	}()
 
 	for msg := make([]byte, 1<<16); ; {
-
 		var err error
 		var msgn int
 		for {
@@ -111,12 +118,12 @@ func (tun *NativeTun) routineNetlinkListener() {
 				break
 			}
 			if !tun.netlinkCancel.ReadyRead() {
-				tun.errors <- fmt.Errorf("netlink socket closed: %s", err.Error())
+				tun.errors <- fmt.Errorf("netlink socket closed: %w", err)
 				return
 			}
 		}
 		if err != nil {
-			tun.errors <- fmt.Errorf("failed to receive netlink message: %s", err.Error())
+			tun.errors <- fmt.Errorf("failed to receive netlink message: %w", err)
 			return
 		}
 
@@ -126,6 +133,7 @@ func (tun *NativeTun) routineNetlinkListener() {
 		default:
 		}
 
+		wasEverUp := false
 		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
 
 			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
@@ -148,14 +156,20 @@ func (tun *NativeTun) routineNetlinkListener() {
 				}
 
 				if info.Flags&unix.IFF_RUNNING != 0 {
-					tun.events <- TUNEventUp
+					tun.events <- EventUp
+					wasEverUp = true
 				}
 
 				if info.Flags&unix.IFF_RUNNING == 0 {
-					tun.events <- TUNEventDown
+					// Don't emit EventDown before we've ever emitted EventUp.
+					// This avoids a startup race with HackListener, which
+					// might detect Up before we have finished reporting Down.
+					if wasEverUp {
+						tun.events <- EventDown
+					}
 				}
 
-				tun.events <- TUNEventMTUUpdate
+				tun.events <- EventMTUUpdate
 
 			default:
 				remain = remain[hdr.Len:]
@@ -164,11 +178,6 @@ func (tun *NativeTun) routineNetlinkListener() {
 	}
 }
 
-func (tun *NativeTun) isUp() (bool, error) {
-	inter, err := net.InterfaceByName(tun.name)
-	return inter.Flags&net.FlagUp != 0, err
-}
-
 func getIFIndex(name string) (int32, error) {
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -198,6 +207,11 @@ func getIFIndex(name string) (int32, error) {
 }
 
 func (tun *NativeTun) setMTU(n int) error {
+	name, err := tun.Name()
+	if err != nil {
+		return err
+	}
+
 	// open datagram socket
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -212,9 +226,8 @@ func (tun *NativeTun) setMTU(n int) error {
 	defer unix.Close(fd)
 
 	// do ioctl call
-
 	var ifr [ifReqSize]byte
-	copy(ifr[:], tun.name)
+	copy(ifr[:], name)
 	*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
 	_, _, errno := unix.Syscall(
 		unix.SYS_IOCTL,
@@ -224,13 +237,18 @@ func (tun *NativeTun) setMTU(n int) error {
 	)
 
 	if errno != 0 {
-		return errors.New("failed to set MTU of TUN device")
+		return fmt.Errorf("failed to set MTU of TUN device: %w", errno)
 	}
 
 	return nil
 }
 
 func (tun *NativeTun) MTU() (int, error) {
+	name, err := tun.Name()
+	if err != nil {
+		return 0, err
+	}
+
 	// open datagram socket
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -247,7 +265,7 @@ func (tun *NativeTun) MTU() (int, error) {
 	// do ioctl call
 
 	var ifr [ifReqSize]byte
-	copy(ifr[:], tun.name)
+	copy(ifr[:], name)
 	_, _, errno := unix.Syscall(
 		unix.SYS_IOCTL,
 		uintptr(fd),
@@ -255,13 +273,22 @@ func (tun *NativeTun) MTU() (int, error) {
 		uintptr(unsafe.Pointer(&ifr[0])),
 	)
 	if errno != 0 {
-		return 0, errors.New("failed to get MTU of TUN device: " + errno.Error())
+		return 0, fmt.Errorf("failed to get MTU of TUN device: %w", errno)
 	}
 
 	return int(*(*int32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ]))), nil
 }
 
 func (tun *NativeTun) Name() (string, error) {
+	tun.nameOnce.Do(tun.initNameCache)
+	return tun.nameCache, tun.nameErr
+}
+
+func (tun *NativeTun) initNameCache() {
+	tun.nameCache, tun.nameErr = tun.nameSlow()
+}
+
+func (tun *NativeTun) nameSlow() (string, error) {
 	sysconn, err := tun.tunFile.SyscallConn()
 	if err != nil {
 		return "", err
@@ -277,18 +304,16 @@ func (tun *NativeTun) Name() (string, error) {
 		)
 	})
 	if err != nil {
-		return "", errors.New("failed to get name of TUN device: " + err.Error())
+		return "", fmt.Errorf("failed to get name of TUN device: %w", err)
 	}
 	if errno != 0 {
-		return "", errors.New("failed to get name of TUN device: " + errno.Error())
+		return "", fmt.Errorf("failed to get name of TUN device: %w", errno)
 	}
-	nullStr := ifr[:]
-	i := bytes.IndexByte(nullStr, 0)
-	if i != -1 {
-		nullStr = nullStr[:i]
+	name := ifr[:]
+	if i := bytes.IndexByte(name, 0); i != -1 {
+		name = name[:i]
 	}
-	tun.name = string(nullStr)
-	return tun.name, nil
+	return string(name), nil
 }
 
 func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
@@ -320,7 +345,7 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 }
 
 func (tun *NativeTun) Flush() error {
-	//TODO: can flushing be implemented by buffering and using sendmmsg?
+	// TODO: can flushing be implemented by buffering and using sendmmsg?
 	return nil
 }
 
@@ -342,7 +367,7 @@ func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
 	}
 }
 
-func (tun *NativeTun) Events() chan TUNEvent {
+func (tun *NativeTun) Events() chan Event {
 	return tun.events
 }
 
@@ -364,9 +389,12 @@ func (tun *NativeTun) Close() error {
 	return err2
 }
 
-func CreateTUN(name string, mtu int) (TUNDevice, error) {
+func CreateTUN(name string, mtu int) (Device, error) {
 	nfd, err := unix.Open(cloneDevicePath, os.O_RDWR, 0)
 	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, fmt.Errorf("CreateTUN(%q) failed; %s does not exist", name, cloneDevicePath)
+		}
 		return nil, err
 	}
 
@@ -374,7 +402,7 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	var flags uint16 = unix.IFF_TUN // | unix.IFF_NO_PI (disabled for TUN status hack)
 	nameBytes := []byte(name)
 	if len(nameBytes) >= unix.IFNAMSIZ {
-		return nil, errors.New("interface name too long")
+		return nil, fmt.Errorf("interface name too long: %w", unix.ENAMETOOLONG)
 	}
 	copy(ifr[:], nameBytes)
 	*(*uint16)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = flags
@@ -400,24 +428,23 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	return CreateTUNFromFile(fd, mtu)
 }
 
-func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
+func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 	tun := &NativeTun{
 		tunFile:                 file,
-		events:                  make(chan TUNEvent, 5),
+		events:                  make(chan Event, 5),
 		errors:                  make(chan error, 5),
 		statusListenersShutdown: make(chan struct{}),
 		nopi:                    false,
 	}
-	var err error
 
-	_, err = tun.Name()
+	name, err := tun.Name()
 	if err != nil {
 		return nil, err
 	}
 
 	// start event listener
 
-	tun.index, err = getIFIndex(tun.name)
+	tun.index, err = getIFIndex(name)
 	if err != nil {
 		return nil, err
 	}
@@ -445,7 +472,7 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 	return tun, nil
 }
 
-func CreateUnmonitoredTUNFromFD(fd int) (TUNDevice, string, error) {
+func CreateUnmonitoredTUNFromFD(fd int) (Device, string, error) {
 	err := unix.SetNonblock(fd, true)
 	if err != nil {
 		return nil, "", err
@@ -453,7 +480,7 @@ func CreateUnmonitoredTUNFromFD(fd int) (TUNDevice, string, error) {
 	file := os.NewFile(uintptr(fd), "/dev/tun")
 	tun := &NativeTun{
 		tunFile: file,
-		events:  make(chan TUNEvent, 5),
+		events:  make(chan Event, 5),
 		errors:  make(chan error, 5),
 		nopi:    true,
 	}

tun/tun_openbsd.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -29,7 +30,7 @@ const _TUNSIFMODE = 0x8004745d
 type NativeTun struct {
 	name        string
 	tunFile     *os.File
-	events      chan TUNEvent
+	events      chan Event
 	errors      chan error
 	routeSocket int
 }
@@ -42,13 +43,41 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 
 	defer close(tun.events)
 
+	check := func() bool {
+		iface, err := net.InterfaceByIndex(tunIfindex)
+		if err != nil {
+			tun.errors <- err
+			return true
+		}
+
+		// Up / Down event
+		up := (iface.Flags & net.FlagUp) != 0
+		if up != statusUp && up {
+			tun.events <- EventUp
+		}
+		if up != statusUp && !up {
+			tun.events <- EventDown
+		}
+		statusUp = up
+
+		// MTU changes
+		if iface.MTU != statusMTU {
+			tun.events <- EventMTUUpdate
+		}
+		statusMTU = iface.MTU
+		return false
+	}
+
+	if check() {
+		return
+	}
+
 	data := make([]byte, os.Getpagesize())
 	for {
-	retry:
 		n, err := unix.Read(tun.routeSocket, data)
 		if err != nil {
 			if errno, ok := err.(syscall.Errno); ok && errno == syscall.EINTR {
-				goto retry
+				continue
 			}
 			tun.errors <- err
 			return
@@ -65,42 +94,13 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 		if ifindex != tunIfindex {
 			continue
 		}
-
-		iface, err := net.InterfaceByIndex(ifindex)
-		if err != nil {
-			tun.errors <- err
+		if check() {
 			return
 		}
-
-		// Up / Down event
-		up := (iface.Flags & net.FlagUp) != 0
-		if up != statusUp && up {
-			tun.events <- TUNEventUp
-		}
-		if up != statusUp && !up {
-			tun.events <- TUNEventDown
-		}
-		statusUp = up
-
-		// MTU changes
-		if iface.MTU != statusMTU {
-			tun.events <- TUNEventMTUUpdate
-		}
-		statusMTU = iface.MTU
 	}
 }
 
-func errorIsEBUSY(err error) bool {
-	if pe, ok := err.(*os.PathError); ok {
-		err = pe.Err
-	}
-	if errno, ok := err.(syscall.Errno); ok && errno == syscall.EBUSY {
-		return true
-	}
-	return false
-}
-
-func CreateTUN(name string, mtu int) (TUNDevice, error) {
+func CreateTUN(name string, mtu int) (Device, error) {
 	ifIndex := -1
 	if name != "tun" {
 		_, err := fmt.Sscanf(name, "tun%d", &ifIndex)
@@ -115,9 +115,9 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	if ifIndex != -1 {
 		tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
 	} else {
-		for ifIndex = 0; ifIndex < 256; ifIndex += 1 {
+		for ifIndex = 0; ifIndex < 256; ifIndex++ {
 			tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
-			if err == nil || !errorIsEBUSY(err) {
+			if err == nil || !errors.Is(err, syscall.EBUSY) {
 				break
 			}
 		}
@@ -139,11 +139,10 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	return tun, err
 }
 
-func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
-
+func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 	tun := &NativeTun{
 		tunFile: file,
-		events:  make(chan TUNEvent, 10),
+		events:  make(chan Event, 10),
 		errors:  make(chan error, 1),
 	}
 
@@ -173,11 +172,14 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 
 	go tun.routineRouteListener(tunIfindex)
 
+	currentMTU, err := tun.MTU()
+	if err != nil || currentMTU != mtu {
 		err = tun.setMTU(mtu)
 		if err != nil {
 			tun.Close()
 			return nil, err
 		}
+	}
 
 	return tun, nil
 }
@@ -197,7 +199,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan TUNEvent {
+func (tun *NativeTun) Events() chan Event {
 	return tun.events
 }
 
@@ -239,7 +241,7 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 }
 
 func (tun *NativeTun) Flush() error {
-	//TODO: can flushing be implemented by buffering and using sendmmsg?
+	// TODO: can flushing be implemented by buffering and using sendmmsg?
 	return nil
 }
 

tun/tun_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2018-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -8,375 +8,226 @@ package tun
 import (
 	"errors"
 	"fmt"
+	"log"
 	"os"
-	"sync"
+	"sync/atomic"
 	"time"
-	"unsafe"
+	_ "unsafe"
 
 	"golang.org/x/sys/windows"
+
 	"golang.zx2c4.com/wireguard/tun/wintun"
 )
 
 const (
-	packetExchangeMax       uint32 = 256                              // Number of packets that may be written at a time
-	packetExchangeAlignment uint32 = 16                               // Number of bytes packets are aligned to in exchange buffers
-	packetSizeMax           uint32 = 0xf000 - packetExchangeAlignment // Maximum packet size
-	packetExchangeSize      uint32 = 0x100000                         // Exchange buffer size (defaults to 1MiB)
-	retryRate                      = 4                                // Number of retries per second to reopen device pipe
-	retryTimeout                   = 30                               // Number of seconds to tolerate adapter unavailable
+	rateMeasurementGranularity = uint64((time.Second / 2) / time.Nanosecond)
+	spinloopRateThreshold      = 800000000 / 8                                   // 800mbps
+	spinloopDuration           = uint64(time.Millisecond / 80 / time.Nanosecond) // ~1gbit/s
 )
 
-type exchgBufRead struct {
-	data   [packetExchangeSize]byte
-	offset uint32
-	avail  uint32
-}
-
-type exchgBufWrite struct {
-	data      [packetExchangeSize]byte
-	offset    uint32
-	packetNum uint32
+type rateJuggler struct {
+	current       uint64
+	nextByteCount uint64
+	nextStartTime int64
+	changing      int32
 }
 
 type NativeTun struct {
-	wt           *wintun.Wintun
-	tunFileRead  *os.File
-	tunFileWrite *os.File
-	tunLock      sync.Mutex
+	wt        *wintun.Adapter
+	handle    windows.Handle
 	close     bool
-	rdBuff       *exchgBufRead
-	wrBuff       *exchgBufWrite
-	events       chan TUNEvent
+	events    chan Event
 	errors    chan error
 	forcedMTU int
+	rate      rateJuggler
+	session   wintun.Session
+	readWait  windows.Handle
 }
 
-func packetAlign(size uint32) uint32 {
-	return (size + (packetExchangeAlignment - 1)) &^ (packetExchangeAlignment - 1)
+var WintunPool, _ = wintun.MakePool("WireGuard")
+var WintunStaticRequestedGUID *windows.GUID
+
+//go:linkname procyield runtime.procyield
+func procyield(cycles uint32)
+
+//go:linkname nanotime runtime.nanotime
+func nanotime() int64
+
+//
+// CreateTUN creates a Wintun interface with the given name. Should a Wintun
+// interface with the same name exist, it is reused.
+//
+func CreateTUN(ifname string, mtu int) (Device, error) {
+	return CreateTUNWithRequestedGUID(ifname, WintunStaticRequestedGUID, mtu)
 }
 
 //
-// CreateTUN creates a Wintun adapter with the given name. Should a Wintun
-// adapter with the same name exist, it is reused.
+// CreateTUNWithRequestedGUID creates a Wintun interface with the given name and
+// a requested GUID. Should a Wintun interface with the same name exist, it is reused.
 //
-func CreateTUN(ifname string) (TUNDevice, error) {
+func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu int) (Device, error) {
 	var err error
-	var wt *wintun.Wintun
+	var wt *wintun.Adapter
 
 	// Does an interface with this name already exist?
-	wt, err = wintun.GetInterface(ifname, 0)
-	if wt == nil {
-		// Interface does not exist or an error occurred. Create one.
-		wt, _, err = wintun.CreateInterface("WireGuard Tunnel Adapter", 0)
+	wt, err = WintunPool.OpenAdapter(ifname)
+	if err == nil {
+		// If so, we delete it, in case it has weird residual configuration.
+		_, err = wt.Delete(true)
 		if err != nil {
-			return nil, fmt.Errorf("wintun.CreateInterface: %v", err)
+			return nil, fmt.Errorf("Error deleting already existing interface: %w", err)
 		}
-	} else if err != nil {
-		// Foreign interface with the same name found.
-		// We could create a Wintun interface under a temporary name. But, should our
-		// process die without deleting this interface first, the interface would remain
-		// orphaned.
-		return nil, fmt.Errorf("wintun.GetInterface: %v", err)
+	}
+	wt, rebootRequired, err := WintunPool.CreateAdapter(ifname, requestedGUID)
+	if err != nil {
+		return nil, fmt.Errorf("Error creating interface: %w", err)
+	}
+	if rebootRequired {
+		log.Println("Windows indicated a reboot is required.")
 	}
 
-	err = wt.SetInterfaceName(ifname)
-	if err != nil {
-		wt.DeleteInterface(0)
-		return nil, fmt.Errorf("wintun.SetInterfaceName: %v", err)
+	forcedMTU := 1420
+	if mtu > 0 {
+		forcedMTU = mtu
 	}
 
-	err = wt.FlushInterface()
-	if err != nil {
-		wt.DeleteInterface(0)
-		return nil, fmt.Errorf("wintun.FlushInterface: %v", err)
-	}
-
-	return &NativeTun{
+	tun := &NativeTun{
 		wt:        wt,
-		rdBuff:    &exchgBufRead{},
-		wrBuff:    &exchgBufWrite{},
-		events:    make(chan TUNEvent, 10),
+		handle:    windows.InvalidHandle,
+		events:    make(chan Event, 10),
 		errors:    make(chan error, 1),
-		forcedMTU: 1500,
-	}, nil
-}
-
-func (tun *NativeTun) openTUN() error {
-	retries := retryTimeout * retryRate
-	if tun.close {
-		return os.ErrClosed
+		forcedMTU: forcedMTU,
 	}
 
-	var err error
-	name := tun.wt.DataFileName()
-	for tun.tunFileRead == nil {
-		tun.tunFileRead, err = os.OpenFile(name, os.O_RDONLY, 0)
+	tun.session, err = wt.StartSession(0x800000) // Ring capacity, 8 MiB
 	if err != nil {
-			if retries > 0 && !tun.close {
-				time.Sleep(time.Second / retryRate)
-				retries--
-				continue
+		tun.wt.Delete(false)
+		close(tun.events)
+		return nil, fmt.Errorf("Error starting session: %w", err)
 	}
-			return err
-		}
-	}
-	for tun.tunFileWrite == nil {
-		tun.tunFileWrite, err = os.OpenFile(name, os.O_WRONLY, 0)
-		if err != nil {
-			if retries > 0 && !tun.close {
-				time.Sleep(time.Second / retryRate)
-				retries--
-				continue
-			}
-			return err
-		}
-	}
-	return nil
-}
-
-func (tun *NativeTun) closeTUN() (err error) {
-	for tun.tunFileRead != nil {
-		tun.tunLock.Lock()
-		if tun.tunFileRead == nil {
-			tun.tunLock.Unlock()
-			break
-		}
-		t := tun.tunFileRead
-		tun.tunFileRead = nil
-		windows.CancelIoEx(windows.Handle(t.Fd()), nil)
-		err = t.Close()
-		tun.tunLock.Unlock()
-		break
-	}
-	for tun.tunFileWrite != nil {
-		tun.tunLock.Lock()
-		if tun.tunFileWrite == nil {
-			tun.tunLock.Unlock()
-			break
-		}
-		t := tun.tunFileWrite
-		tun.tunFileWrite = nil
-		windows.CancelIoEx(windows.Handle(t.Fd()), nil)
-		err2 := t.Close()
-		tun.tunLock.Unlock()
-		if err == nil {
-			err = err2
-		}
-		break
-	}
-	return
-}
-
-func (tun *NativeTun) getTUN() (read *os.File, write *os.File, err error) {
-	read, write = tun.tunFileRead, tun.tunFileWrite
-	if read == nil || write == nil {
-		read, write = nil, nil
-		tun.tunLock.Lock()
-		if tun.tunFileRead != nil && tun.tunFileWrite != nil {
-			read, write = tun.tunFileRead, tun.tunFileWrite
-			tun.tunLock.Unlock()
-			return
-		}
-		err = tun.closeTUN()
-		if err != nil {
-			tun.tunLock.Unlock()
-			return
-		}
-		err = tun.openTUN()
-		if err == nil {
-			read, write = tun.tunFileRead, tun.tunFileWrite
-		}
-		tun.tunLock.Unlock()
-		return
-	}
-	return
+	tun.readWait = tun.session.ReadWaitEvent()
+	return tun, nil
 }
 
 func (tun *NativeTun) Name() (string, error) {
-	return tun.wt.GetInterfaceName()
+	return tun.wt.Name()
 }
 
 func (tun *NativeTun) File() *os.File {
 	return nil
 }
 
-func (tun *NativeTun) Events() chan TUNEvent {
+func (tun *NativeTun) Events() chan Event {
 	return tun.events
 }
 
 func (tun *NativeTun) Close() error {
 	tun.close = true
-	err1 := tun.closeTUN()
-
-	if tun.events != nil {
+	tun.session.End()
+	var err error
+	if tun.wt != nil {
+		_, err = tun.wt.Delete(false)
+	}
 	close(tun.events)
-	}
-
-	_, _, err2 := tun.wt.DeleteInterface(0)
-	if err1 == nil {
-		err1 = err2
-	}
-
-	return err1
+	return err
 }
 
 func (tun *NativeTun) MTU() (int, error) {
 	return tun.forcedMTU, nil
 }
 
-//TODO: This is a temporary hack. We really need to be monitoring the interface in real time and adapting to MTU changes.
+// TODO: This is a temporary hack. We really need to be monitoring the interface in real time and adapting to MTU changes.
 func (tun *NativeTun) ForceMTU(mtu int) {
 	tun.forcedMTU = mtu
 }
 
+// Note: Read() and Write() assume the caller comes only from a single thread; there's no locking.
+
 func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
+retry:
 	select {
 	case err := <-tun.errors:
 		return 0, err
 	default:
 	}
-
+	start := nanotime()
+	shouldSpin := atomic.LoadUint64(&tun.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&tun.rate.nextStartTime)) <= rateMeasurementGranularity*2
 	for {
-		if tun.rdBuff.offset+packetExchangeAlignment <= tun.rdBuff.avail {
-			// Get packet from the exchange buffer.
-			packet := tun.rdBuff.data[tun.rdBuff.offset:]
-			size := *(*uint32)(unsafe.Pointer(&packet[0]))
-			pSize := packetAlign(packetExchangeAlignment + size)
-			if packetSizeMax < size || tun.rdBuff.avail < tun.rdBuff.offset+pSize {
-				// Invalid packet size.
-				tun.rdBuff.avail = 0
-				continue
-			}
-			packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
-
-			// Copy data.
-			copy(buff[offset:], packet)
-			tun.rdBuff.offset += pSize
-			return int(size), nil
-		}
-
-		// Get TUN data pipe.
-		file, _, err := tun.getTUN()
-		if err != nil {
-			return 0, err
-		}
-
-		// Fill queue.
-		retries := 1000
-		for {
-			n, err := file.Read(tun.rdBuff.data[:])
-			if err != nil {
-				tun.rdBuff.offset = 0
-				tun.rdBuff.avail = 0
-				pe, ok := err.(*os.PathError)
 		if tun.close {
 			return 0, os.ErrClosed
 		}
-				if retries > 0 && ok && pe.Err == windows.ERROR_OPERATION_ABORTED {
-					retries--
+		packet, err := tun.session.ReceivePacket()
+		switch err {
+		case nil:
+			packetSize := len(packet)
+			copy(buff[offset:], packet)
+			tun.session.ReleaseReceivePacket(packet)
+			tun.rate.update(uint64(packetSize))
+			return packetSize, nil
+		case windows.ERROR_NO_MORE_ITEMS:
+			if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
+				windows.WaitForSingleObject(tun.readWait, windows.INFINITE)
+				goto retry
+			}
+			procyield(1)
 			continue
+		case windows.ERROR_HANDLE_EOF:
+			return 0, os.ErrClosed
+		case windows.ERROR_INVALID_DATA:
+			return 0, errors.New("Send ring corrupt")
 		}
-				if ok && pe.Err == windows.ERROR_HANDLE_EOF {
-					tun.closeTUN()
-					break
-				}
-				return 0, err
-			}
-			tun.rdBuff.offset = 0
-			tun.rdBuff.avail = uint32(n)
-			break
-		}
+		return 0, fmt.Errorf("Read failed: %w", err)
 	}
 }
 
-// Note: flush() and putTunPacket() assume the caller comes only from a single thread; there's no locking.
-
 func (tun *NativeTun) Flush() error {
-	if tun.wrBuff.offset == 0 {
-		return nil
-	}
-
-	for {
-		// Get TUN data pipe.
-		_, file, err := tun.getTUN()
-		if err != nil {
-			return err
-		}
-
-		// Flush write buffer.
-		retries := 1000
-		for {
-			_, err = file.Write(tun.wrBuff.data[:tun.wrBuff.offset])
-			tun.wrBuff.packetNum = 0
-			tun.wrBuff.offset = 0
-			if err != nil {
-				pe, ok := err.(*os.PathError)
-				if tun.close {
-					return os.ErrClosed
-				}
-				if retries > 0 && ok && pe.Err == windows.ERROR_OPERATION_ABORTED {
-					retries--
-					continue
-				}
-				if ok && pe.Err == windows.ERROR_HANDLE_EOF {
-					tun.closeTUN()
-					break
-				}
-				return err
-			}
-			return nil
-		}
-	}
-}
-
-func (tun *NativeTun) putTunPacket(buff []byte) error {
-	size := uint32(len(buff))
-	if size == 0 {
-		return errors.New("Empty packet")
-	}
-	if size > packetSizeMax {
-		return errors.New("Packet too big")
-	}
-	pSize := packetAlign(packetExchangeAlignment + size)
-
-	if tun.wrBuff.packetNum >= packetExchangeMax || tun.wrBuff.offset+pSize >= packetExchangeSize {
-		// Exchange buffer is full -> flush first.
-		err := tun.Flush()
-		if err != nil {
-			return err
-		}
-	}
-
-	// Write packet to the exchange buffer.
-	packet := tun.wrBuff.data[tun.wrBuff.offset : tun.wrBuff.offset+pSize]
-	*(*uint32)(unsafe.Pointer(&packet[0])) = size
-	packet = packet[packetExchangeAlignment : packetExchangeAlignment+size]
-	copy(packet, buff)
-
-	tun.wrBuff.packetNum++
-	tun.wrBuff.offset += pSize
-
 	return nil
 }
 
 func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
-	err := tun.putTunPacket(buff[offset:])
-	if err != nil {
-		return 0, err
+	if tun.close {
+		return 0, os.ErrClosed
 	}
-	return len(buff) - offset, nil
+
+	packetSize := len(buff) - offset
+	tun.rate.update(uint64(packetSize))
+
+	packet, err := tun.session.AllocateSendPacket(packetSize)
+	if err == nil {
+		copy(packet, buff[offset:])
+		tun.session.SendPacket(packet)
+		return packetSize, nil
+	}
+	switch err {
+	case windows.ERROR_HANDLE_EOF:
+		return 0, os.ErrClosed
+	case windows.ERROR_BUFFER_OVERFLOW:
+		return 0, nil // Dropping when ring is full.
+	}
+	return 0, fmt.Errorf("Write failed: %w", err)
 }
 
-//
-// GUID returns Windows adapter instance ID.
-//
-func (tun *NativeTun) GUID() windows.GUID {
-	return tun.wt.CfgInstanceID
-}
-
-//
-// GUID returns Windows adapter instance ID.
-//
+// LUID returns Windows interface instance ID.
 func (tun *NativeTun) LUID() uint64 {
-	return ((uint64(tun.wt.LUIDIndex) & ((1 << 24) - 1)) << 24) | ((uint64(tun.wt.IfType) & ((1 << 16) - 1)) << 48)
+	return tun.wt.LUID()
+}
+
+// RunningVersion returns the running version of the Wintun driver.
+func (tun *NativeTun) RunningVersion() (version uint32, err error) {
+	return wintun.RunningVersion()
+}
+
+func (rate *rateJuggler) update(packetLen uint64) {
+	now := nanotime()
+	total := atomic.AddUint64(&rate.nextByteCount, packetLen)
+	period := uint64(now - atomic.LoadInt64(&rate.nextStartTime))
+	if period >= rateMeasurementGranularity {
+		if !atomic.CompareAndSwapInt32(&rate.changing, 0, 1) {
+			return
+		}
+		atomic.StoreInt64(&rate.nextStartTime, now)
+		atomic.StoreUint64(&rate.current, total*uint64(time.Second/time.Nanosecond)/period)
+		atomic.StoreUint64(&rate.nextByteCount, 0)
+		atomic.StoreInt32(&rate.changing, 0)
+	}
 }

tun/tuntest/tuntest.go

@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package tuntest
+
+import (
+	"encoding/binary"
+	"io"
+	"net"
+	"os"
+
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+func Ping(dst, src net.IP) []byte {
+	localPort := uint16(1337)
+	seq := uint16(0)
+
+	payload := make([]byte, 4)
+	binary.BigEndian.PutUint16(payload[0:], localPort)
+	binary.BigEndian.PutUint16(payload[2:], seq)
+
+	return genICMPv4(payload, dst, src)
+}
+
+// Checksum is the "internet checksum" from https://tools.ietf.org/html/rfc1071.
+func checksum(buf []byte, initial uint16) uint16 {
+	v := uint32(initial)
+	for i := 0; i < len(buf)-1; i += 2 {
+		v += uint32(binary.BigEndian.Uint16(buf[i:]))
+	}
+	if len(buf)%2 == 1 {
+		v += uint32(buf[len(buf)-1]) << 8
+	}
+	for v > 0xffff {
+		v = (v >> 16) + (v & 0xffff)
+	}
+	return ^uint16(v)
+}
+
+func genICMPv4(payload []byte, dst, src net.IP) []byte {
+	const (
+		icmpv4ProtocolNumber = 1
+		icmpv4Echo           = 8
+		icmpv4ChecksumOffset = 2
+		icmpv4Size           = 8
+		ipv4Size             = 20
+		ipv4TotalLenOffset   = 2
+		ipv4ChecksumOffset   = 10
+		ttl                  = 65
+		headerSize           = ipv4Size + icmpv4Size
+	)
+
+	pkt := make([]byte, headerSize+len(payload))
+
+	ip := pkt[0:ipv4Size]
+	icmpv4 := pkt[ipv4Size : ipv4Size+icmpv4Size]
+
+	// https://tools.ietf.org/html/rfc792
+	icmpv4[0] = icmpv4Echo // type
+	icmpv4[1] = 0          // code
+	chksum := ^checksum(icmpv4, checksum(payload, 0))
+	binary.BigEndian.PutUint16(icmpv4[icmpv4ChecksumOffset:], chksum)
+
+	// https://tools.ietf.org/html/rfc760 section 3.1
+	length := uint16(len(pkt))
+	ip[0] = (4 << 4) | (ipv4Size / 4)
+	binary.BigEndian.PutUint16(ip[ipv4TotalLenOffset:], length)
+	ip[8] = ttl
+	ip[9] = icmpv4ProtocolNumber
+	copy(ip[12:], src.To4())
+	copy(ip[16:], dst.To4())
+	chksum = ^checksum(ip[:], 0)
+	binary.BigEndian.PutUint16(ip[ipv4ChecksumOffset:], chksum)
+
+	copy(pkt[headerSize:], payload)
+	return pkt
+}
+
+// TODO(crawshaw): find a reusable home for this. package devicetest?
+type ChannelTUN struct {
+	Inbound  chan []byte // incoming packets, closed on TUN close
+	Outbound chan []byte // outbound packets, blocks forever on TUN close
+
+	closed chan struct{}
+	events chan tun.Event
+	tun    chTun
+}
+
+func NewChannelTUN() *ChannelTUN {
+	c := &ChannelTUN{
+		Inbound:  make(chan []byte),
+		Outbound: make(chan []byte),
+		closed:   make(chan struct{}),
+		events:   make(chan tun.Event, 1),
+	}
+	c.tun.c = c
+	c.events <- tun.EventUp
+	return c
+}
+
+func (c *ChannelTUN) TUN() tun.Device {
+	return &c.tun
+}
+
+type chTun struct {
+	c *ChannelTUN
+}
+
+func (t *chTun) File() *os.File { return nil }
+
+func (t *chTun) Read(data []byte, offset int) (int, error) {
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case msg := <-t.c.Outbound:
+		return copy(data[offset:], msg), nil
+	}
+}
+
+// Write is called by the wireguard device to deliver a packet for routing.
+func (t *chTun) Write(data []byte, offset int) (int, error) {
+	if offset == -1 {
+		close(t.c.closed)
+		close(t.c.events)
+		return 0, io.EOF
+	}
+	msg := make([]byte, len(data)-offset)
+	copy(msg, data[offset:])
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case t.c.Inbound <- msg:
+		return len(data) - offset, nil
+	}
+}
+
+const DefaultMTU = 1420
+
+func (t *chTun) Flush() error           { return nil }
+func (t *chTun) MTU() (int, error)      { return DefaultMTU, nil }
+func (t *chTun) Name() (string, error)  { return "loopbackTun1", nil }
+func (t *chTun) Events() chan tun.Event { return t.c.events }
+func (t *chTun) Close() error {
+	t.Write(nil, -1)
+	return nil
+}

tun/wintun/dll_fromfile_windows.go

@@ -0,0 +1,54 @@
+// +build !load_wintun_from_rsrc
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type lazyDLL struct {
+	Name   string
+	mu     sync.Mutex
+	module windows.Handle
+	onLoad func(d *lazyDLL)
+}
+
+func (d *lazyDLL) Load() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
+		return nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.module != 0 {
+		return nil
+	}
+
+	const (
+		LOAD_LIBRARY_SEARCH_APPLICATION_DIR = 0x00000200
+		LOAD_LIBRARY_SEARCH_SYSTEM32        = 0x00000800
+	)
+	module, err := windows.LoadLibraryEx(d.Name, 0, LOAD_LIBRARY_SEARCH_APPLICATION_DIR|LOAD_LIBRARY_SEARCH_SYSTEM32)
+	if err != nil {
+		return fmt.Errorf("Unable to load library: %w", err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
+	if d.onLoad != nil {
+		d.onLoad(d)
+	}
+	return nil
+}
+
+func (p *lazyProc) nameToAddr() (uintptr, error) {
+	return windows.GetProcAddress(p.dll.module, p.Name)
+}

tun/wintun/dll_fromrsrc_windows.go

@@ -0,0 +1,62 @@
+// +build load_wintun_from_rsrc
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+
+	"golang.zx2c4.com/wireguard/tun/wintun/memmod"
+	"golang.zx2c4.com/wireguard/tun/wintun/resource"
+)
+
+type lazyDLL struct {
+	Name   string
+	mu     sync.Mutex
+	module *memmod.Module
+	onLoad func(d *lazyDLL)
+}
+
+func (d *lazyDLL) Load() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
+		return nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.module != nil {
+		return nil
+	}
+
+	const ourModule windows.Handle = 0
+	resInfo, err := resource.FindByName(ourModule, d.Name, resource.RT_RCDATA)
+	if err != nil {
+		return fmt.Errorf("Unable to find \"%v\" RCDATA resource: %w", d.Name, err)
+	}
+	data, err := resource.Load(ourModule, resInfo)
+	if err != nil {
+		return fmt.Errorf("Unable to load resource: %w", err)
+	}
+	module, err := memmod.LoadLibrary(data)
+	if err != nil {
+		return fmt.Errorf("Unable to load library: %w", err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
+	if d.onLoad != nil {
+		d.onLoad(d)
+	}
+	return nil
+}
+
+func (p *lazyProc) nameToAddr() (uintptr, error) {
+	return p.dll.module.ProcAddressByName(p.Name)
+}

tun/wintun/dll_windows.go

@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+)
+
+func newLazyDLL(name string, onLoad func(d *lazyDLL)) *lazyDLL {
+	return &lazyDLL{Name: name, onLoad: onLoad}
+}
+
+func (d *lazyDLL) NewProc(name string) *lazyProc {
+	return &lazyProc{dll: d, Name: name}
+}
+
+type lazyProc struct {
+	Name string
+	mu   sync.Mutex
+	dll  *lazyDLL
+	addr uintptr
+}
+
+func (p *lazyProc) Find() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr))) != nil {
+		return nil
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.addr != 0 {
+		return nil
+	}
+
+	err := p.dll.Load()
+	if err != nil {
+		return fmt.Errorf("Error loading %v DLL: %w", p.dll.Name, err)
+	}
+	addr, err := p.nameToAddr()
+	if err != nil {
+		return fmt.Errorf("Error getting %v address: %w", p.Name, err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr)), unsafe.Pointer(addr))
+	return nil
+}
+
+func (p *lazyProc) Addr() uintptr {
+	err := p.Find()
+	if err != nil {
+		panic(err)
+	}
+	return p.addr
+}

tun/wintun/guid/guid_windows.go

@@ -1,41 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
- */
-
-package guid
-
-import (
-	"fmt"
-	"syscall"
-
-	"golang.org/x/sys/windows"
-)
-
-//sys	clsidFromString(lpsz *uint16, pclsid *windows.GUID) (err error) [failretval!=0] = ole32.CLSIDFromString
-
-//
-// FromString parses "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}" string to GUID.
-//
-func FromString(str string) (*windows.GUID, error) {
-	strUTF16, err := syscall.UTF16PtrFromString(str)
-	if err != nil {
-		return nil, err
-	}
-	guid := &windows.GUID{}
-	err = clsidFromString(strUTF16, guid)
-	if err != nil {
-		return nil, err
-	}
-	return guid, nil
-}
-
-//
-// ToString function converts GUID to string
-// "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}".
-//
-// The resulting string is uppercase.
-//
-func ToString(guid *windows.GUID) string {
-	return fmt.Sprintf("{%08X-%04X-%04X-%04X-%012X}", guid.Data1, guid.Data2, guid.Data3, guid.Data4[:2], guid.Data4[2:])
-}

tun/wintun/guid/mksyscall.go

@@ -1,8 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
- */
-
-package guid
-
-//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zguid_windows.go guid_windows.go

tun/wintun/memmod/memmod_windows.go

@@ -0,0 +1,620 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+import (
+	"errors"
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type addressList struct {
+	next    *addressList
+	address uintptr
+}
+
+func (head *addressList) free() {
+	for node := head; node != nil; node = node.next {
+		windows.VirtualFree(node.address, 0, windows.MEM_RELEASE)
+	}
+}
+
+type Module struct {
+	headers       *IMAGE_NT_HEADERS
+	codeBase      uintptr
+	modules       []windows.Handle
+	initialized   bool
+	isDLL         bool
+	isRelocated   bool
+	nameExports   map[string]uint16
+	entry         uintptr
+	blockedMemory *addressList
+}
+
+func (module *Module) headerDirectory(idx int) *IMAGE_DATA_DIRECTORY {
+	return &module.headers.OptionalHeader.DataDirectory[idx]
+}
+
+func (module *Module) copySections(address uintptr, size uintptr, old_headers *IMAGE_NT_HEADERS) error {
+	sections := module.headers.Sections()
+	for i := range sections {
+		if sections[i].SizeOfRawData == 0 {
+			// Section doesn't contain data in the dll itself, but may define uninitialized data.
+			sectionSize := old_headers.OptionalHeader.SectionAlignment
+			if sectionSize == 0 {
+				continue
+			}
+			dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
+				uintptr(sectionSize),
+				windows.MEM_COMMIT,
+				windows.PAGE_READWRITE)
+			if err != nil {
+				return fmt.Errorf("Error allocating section: %w", err)
+			}
+
+			// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
+			dest = module.codeBase + uintptr(sections[i].VirtualAddress)
+			// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
+			sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
+			var dst []byte
+			unsafeSlice(unsafe.Pointer(&dst), a2p(dest), int(sectionSize))
+			for j := range dst {
+				dst[j] = 0
+			}
+			continue
+		}
+
+		if size < uintptr(sections[i].PointerToRawData+sections[i].SizeOfRawData) {
+			return errors.New("Incomplete section")
+		}
+
+		// Commit memory block and copy data from dll.
+		dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
+			uintptr(sections[i].SizeOfRawData),
+			windows.MEM_COMMIT,
+			windows.PAGE_READWRITE)
+		if err != nil {
+			return fmt.Errorf("Error allocating memory block: %w", err)
+		}
+
+		// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
+		memcpy(
+			module.codeBase+uintptr(sections[i].VirtualAddress),
+			address+uintptr(sections[i].PointerToRawData),
+			uintptr(sections[i].SizeOfRawData))
+		// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
+		sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
+	}
+
+	return nil
+}
+
+func (module *Module) realSectionSize(section *IMAGE_SECTION_HEADER) uintptr {
+	size := section.SizeOfRawData
+	if size != 0 {
+		return uintptr(size)
+	}
+	if (section.Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA) != 0 {
+		return uintptr(module.headers.OptionalHeader.SizeOfInitializedData)
+	}
+	if (section.Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA) != 0 {
+		return uintptr(module.headers.OptionalHeader.SizeOfUninitializedData)
+	}
+	return 0
+}
+
+type sectionFinalizeData struct {
+	address         uintptr
+	alignedAddress  uintptr
+	size            uintptr
+	characteristics uint32
+	last            bool
+}
+
+func (module *Module) finalizeSection(sectionData *sectionFinalizeData) error {
+	if sectionData.size == 0 {
+		return nil
+	}
+
+	if (sectionData.characteristics & IMAGE_SCN_MEM_DISCARDABLE) != 0 {
+		// Section is not needed any more and can safely be freed.
+		if sectionData.address == sectionData.alignedAddress &&
+			(sectionData.last ||
+				(sectionData.size%uintptr(module.headers.OptionalHeader.SectionAlignment)) == 0) {
+			// Only allowed to decommit whole pages.
+			windows.VirtualFree(sectionData.address, sectionData.size, windows.MEM_DECOMMIT)
+		}
+		return nil
+	}
+
+	// determine protection flags based on characteristics
+	var ProtectionFlags = [8]uint32{
+		windows.PAGE_NOACCESS,          // not writeable, not readable, not executable
+		windows.PAGE_EXECUTE,           // not writeable, not readable, executable
+		windows.PAGE_READONLY,          // not writeable, readable, not executable
+		windows.PAGE_EXECUTE_READ,      // not writeable, readable, executable
+		windows.PAGE_WRITECOPY,         // writeable, not readable, not executable
+		windows.PAGE_EXECUTE_WRITECOPY, // writeable, not readable, executable
+		windows.PAGE_READWRITE,         // writeable, readable, not executable
+		windows.PAGE_EXECUTE_READWRITE, // writeable, readable, executable
+	}
+	protect := ProtectionFlags[sectionData.characteristics>>29]
+	if (sectionData.characteristics & IMAGE_SCN_MEM_NOT_CACHED) != 0 {
+		protect |= windows.PAGE_NOCACHE
+	}
+
+	// Change memory access flags.
+	var oldProtect uint32
+	err := windows.VirtualProtect(sectionData.address, sectionData.size, protect, &oldProtect)
+	if err != nil {
+		return fmt.Errorf("Error protecting memory page: %w", err)
+	}
+
+	return nil
+}
+
+func (module *Module) finalizeSections() error {
+	sections := module.headers.Sections()
+	imageOffset := module.headers.OptionalHeader.imageOffset()
+	sectionData := sectionFinalizeData{}
+	sectionData.address = uintptr(sections[0].PhysicalAddress()) | imageOffset
+	sectionData.alignedAddress = alignDown(sectionData.address, uintptr(module.headers.OptionalHeader.SectionAlignment))
+	sectionData.size = module.realSectionSize(&sections[0])
+	sectionData.characteristics = sections[0].Characteristics
+
+	// Loop through all sections and change access flags.
+	for i := uint16(1); i < module.headers.FileHeader.NumberOfSections; i++ {
+		sectionAddress := uintptr(sections[i].PhysicalAddress()) | imageOffset
+		alignedAddress := alignDown(sectionAddress, uintptr(module.headers.OptionalHeader.SectionAlignment))
+		sectionSize := module.realSectionSize(&sections[i])
+		// Combine access flags of all sections that share a page.
+		// TODO: We currently share flags of a trailing large section with the page of a first small section. This should be optimized.
+		if sectionData.alignedAddress == alignedAddress || sectionData.address+sectionData.size > alignedAddress {
+			// Section shares page with previous.
+			if (sections[i].Characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 || (sectionData.characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 {
+				sectionData.characteristics = (sectionData.characteristics | sections[i].Characteristics) &^ IMAGE_SCN_MEM_DISCARDABLE
+			} else {
+				sectionData.characteristics |= sections[i].Characteristics
+			}
+			sectionData.size = sectionAddress + sectionSize - sectionData.address
+			continue
+		}
+
+		err := module.finalizeSection(&sectionData)
+		if err != nil {
+			return fmt.Errorf("Error finalizing section: %w", err)
+		}
+		sectionData.address = sectionAddress
+		sectionData.alignedAddress = alignedAddress
+		sectionData.size = sectionSize
+		sectionData.characteristics = sections[i].Characteristics
+	}
+	sectionData.last = true
+	err := module.finalizeSection(&sectionData)
+	if err != nil {
+		return fmt.Errorf("Error finalizing section: %w", err)
+	}
+	return nil
+}
+
+func (module *Module) executeTLS() {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_TLS)
+	if directory.VirtualAddress == 0 {
+		return
+	}
+
+	tls := (*IMAGE_TLS_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	callback := tls.AddressOfCallbacks
+	if callback != 0 {
+		for {
+			f := *(*uintptr)(a2p(callback))
+			if f == 0 {
+				break
+			}
+			syscall.Syscall(f, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), uintptr(0))
+			callback += unsafe.Sizeof(f)
+		}
+	}
+}
+
+func (module *Module) performBaseRelocation(delta uintptr) (relocated bool, err error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_BASERELOC)
+	if directory.Size == 0 {
+		return delta == 0, nil
+	}
+
+	relocationHdr := (*IMAGE_BASE_RELOCATION)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	for relocationHdr.VirtualAddress > 0 {
+		dest := module.codeBase + uintptr(relocationHdr.VirtualAddress)
+
+		var relInfos []uint16
+		unsafeSlice(
+			unsafe.Pointer(&relInfos),
+			a2p(uintptr(unsafe.Pointer(relocationHdr))+unsafe.Sizeof(*relocationHdr)),
+			int((uintptr(relocationHdr.SizeOfBlock)-unsafe.Sizeof(*relocationHdr))/unsafe.Sizeof(relInfos[0])))
+		for _, relInfo := range relInfos {
+			// The upper 4 bits define the type of relocation.
+			relType := relInfo >> 12
+			// The lower 12 bits define the offset.
+			relOffset := uintptr(relInfo & 0xfff)
+
+			switch relType {
+			case IMAGE_REL_BASED_ABSOLUTE:
+				// Skip relocation.
+
+			case IMAGE_REL_BASED_LOW:
+				*(*uint16)(a2p(dest + relOffset)) += uint16(delta & 0xffff)
+				break
+
+			case IMAGE_REL_BASED_HIGH:
+				*(*uint16)(a2p(dest + relOffset)) += uint16(uint32(delta) >> 16)
+				break
+
+			case IMAGE_REL_BASED_HIGHLOW:
+				*(*uint32)(a2p(dest + relOffset)) += uint32(delta)
+
+			case IMAGE_REL_BASED_DIR64:
+				*(*uint64)(a2p(dest + relOffset)) += uint64(delta)
+
+			case IMAGE_REL_BASED_THUMB_MOV32:
+				inst := *(*uint32)(a2p(dest + relOffset))
+				imm16 := ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
+					((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
+				if (inst & 0x8000fbf0) != 0x0000f240 {
+					return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVW", inst)
+				}
+				imm16 += uint32(delta) & 0xffff
+				hiDelta := (uint32(delta&0xffff0000) >> 16) + ((imm16 & 0xffff0000) >> 16)
+				*(*uint32)(a2p(dest + relOffset)) = (inst & 0x8f00fbf0) + ((imm16 >> 1) & 0x0400) +
+					((imm16 >> 12) & 0x000f) +
+					((imm16 << 20) & 0x70000000) +
+					((imm16 << 16) & 0xff0000)
+				if hiDelta != 0 {
+					inst = *(*uint32)(a2p(dest + relOffset + 4))
+					imm16 = ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
+						((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
+					if (inst & 0x8000fbf0) != 0x0000f2c0 {
+						return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVT", inst)
+					}
+					imm16 += hiDelta
+					if imm16 > 0xffff {
+						return false, fmt.Errorf("Resulting immediate value won't fit: %08x", imm16)
+					}
+					*(*uint32)(a2p(dest + relOffset + 4)) = (inst & 0x8f00fbf0) +
+						((imm16 >> 1) & 0x0400) +
+						((imm16 >> 12) & 0x000f) +
+						((imm16 << 20) & 0x70000000) +
+						((imm16 << 16) & 0xff0000)
+				}
+
+			default:
+				return false, fmt.Errorf("Unsupported relocation: %v", relType)
+			}
+		}
+
+		// Advance to next relocation block.
+		relocationHdr = (*IMAGE_BASE_RELOCATION)(a2p(uintptr(unsafe.Pointer(relocationHdr)) + uintptr(relocationHdr.SizeOfBlock)))
+	}
+	return true, nil
+}
+
+func (module *Module) buildImportTable() error {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_IMPORT)
+	if directory.Size == 0 {
+		return nil
+	}
+
+	module.modules = make([]windows.Handle, 0, 16)
+	importDesc := (*IMAGE_IMPORT_DESCRIPTOR)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	for !isBadReadPtr(uintptr(unsafe.Pointer(importDesc)), unsafe.Sizeof(*importDesc)) && importDesc.Name != 0 {
+		handle, err := windows.LoadLibraryEx(windows.BytePtrToString((*byte)(a2p(module.codeBase+uintptr(importDesc.Name)))), 0, windows.LOAD_LIBRARY_SEARCH_SYSTEM32)
+		if err != nil {
+			return fmt.Errorf("Error loading module: %w", err)
+		}
+		var thunkRef, funcRef *uintptr
+		if importDesc.OriginalFirstThunk() != 0 {
+			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.OriginalFirstThunk())))
+			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+		} else {
+			// No hint table.
+			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+		}
+		for *thunkRef != 0 {
+			if IMAGE_SNAP_BY_ORDINAL(*thunkRef) {
+				*funcRef, err = windows.GetProcAddressByOrdinal(handle, IMAGE_ORDINAL(*thunkRef))
+			} else {
+				thunkData := (*IMAGE_IMPORT_BY_NAME)(a2p(module.codeBase + *thunkRef))
+				*funcRef, err = windows.GetProcAddress(handle, windows.BytePtrToString(&thunkData.Name[0]))
+			}
+			if err != nil {
+				windows.FreeLibrary(handle)
+				return fmt.Errorf("Error getting function address: %w", err)
+			}
+			thunkRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(thunkRef)) + unsafe.Sizeof(*thunkRef)))
+			funcRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(funcRef)) + unsafe.Sizeof(*funcRef)))
+		}
+		module.modules = append(module.modules, handle)
+		importDesc = (*IMAGE_IMPORT_DESCRIPTOR)(a2p(uintptr(unsafe.Pointer(importDesc)) + unsafe.Sizeof(*importDesc)))
+	}
+	return nil
+}
+
+func (module *Module) buildNameExports() error {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if exports.NumberOfNames == 0 || exports.NumberOfFunctions == 0 {
+		return errors.New("No functions exported")
+	}
+	if exports.NumberOfNames == 0 {
+		return errors.New("No functions exported by name")
+	}
+	var nameRefs []uint32
+	unsafeSlice(unsafe.Pointer(&nameRefs), a2p(module.codeBase+uintptr(exports.AddressOfNames)), int(exports.NumberOfNames))
+	var ordinals []uint16
+	unsafeSlice(unsafe.Pointer(&ordinals), a2p(module.codeBase+uintptr(exports.AddressOfNameOrdinals)), int(exports.NumberOfNames))
+	module.nameExports = make(map[string]uint16)
+	for i := range nameRefs {
+		nameArray := windows.BytePtrToString((*byte)(a2p(module.codeBase + uintptr(nameRefs[i]))))
+		module.nameExports[nameArray] = ordinals[i]
+	}
+	return nil
+}
+
+// LoadLibrary loads module image to memory.
+func LoadLibrary(data []byte) (module *Module, err error) {
+	addr := uintptr(unsafe.Pointer(&data[0]))
+	size := uintptr(len(data))
+	if size < unsafe.Sizeof(IMAGE_DOS_HEADER{}) {
+		return nil, errors.New("Incomplete IMAGE_DOS_HEADER")
+	}
+	dosHeader := (*IMAGE_DOS_HEADER)(a2p(addr))
+	if dosHeader.E_magic != IMAGE_DOS_SIGNATURE {
+		return nil, fmt.Errorf("Not an MS-DOS binary (provided: %x, expected: %x)", dosHeader.E_magic, IMAGE_DOS_SIGNATURE)
+	}
+	if (size < uintptr(dosHeader.E_lfanew)+unsafe.Sizeof(IMAGE_NT_HEADERS{})) {
+		return nil, errors.New("Incomplete IMAGE_NT_HEADERS")
+	}
+	oldHeader := (*IMAGE_NT_HEADERS)(a2p(addr + uintptr(dosHeader.E_lfanew)))
+	if oldHeader.Signature != IMAGE_NT_SIGNATURE {
+		return nil, fmt.Errorf("Not an NT binary (provided: %x, expected: %x)", oldHeader.Signature, IMAGE_NT_SIGNATURE)
+	}
+	if oldHeader.FileHeader.Machine != imageFileProcess {
+		return nil, fmt.Errorf("Foreign platform (provided: %x, expected: %x)", oldHeader.FileHeader.Machine, imageFileProcess)
+	}
+	if (oldHeader.OptionalHeader.SectionAlignment & 1) != 0 {
+		return nil, errors.New("Unaligned section")
+	}
+	lastSectionEnd := uintptr(0)
+	sections := oldHeader.Sections()
+	optionalSectionSize := oldHeader.OptionalHeader.SectionAlignment
+	for i := range sections {
+		var endOfSection uintptr
+		if sections[i].SizeOfRawData == 0 {
+			// Section without data in the DLL
+			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(optionalSectionSize)
+		} else {
+			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(sections[i].SizeOfRawData)
+		}
+		if endOfSection > lastSectionEnd {
+			lastSectionEnd = endOfSection
+		}
+	}
+	alignedImageSize := alignUp(uintptr(oldHeader.OptionalHeader.SizeOfImage), uintptr(oldHeader.OptionalHeader.SectionAlignment))
+	if alignedImageSize != alignUp(lastSectionEnd, uintptr(oldHeader.OptionalHeader.SectionAlignment)) {
+		return nil, errors.New("Section is not page-aligned")
+	}
+
+	module = &Module{isDLL: (oldHeader.FileHeader.Characteristics & IMAGE_FILE_DLL) != 0}
+	defer func() {
+		if err != nil {
+			module.Free()
+			module = nil
+		}
+	}()
+
+	// Reserve memory for image of library.
+	// TODO: Is it correct to commit the complete memory region at once? Calling DllEntry raises an exception if we don't.
+	module.codeBase, err = windows.VirtualAlloc(oldHeader.OptionalHeader.ImageBase,
+		alignedImageSize,
+		windows.MEM_RESERVE|windows.MEM_COMMIT,
+		windows.PAGE_READWRITE)
+	if err != nil {
+		// Try to allocate memory at arbitrary position.
+		module.codeBase, err = windows.VirtualAlloc(0,
+			alignedImageSize,
+			windows.MEM_RESERVE|windows.MEM_COMMIT,
+			windows.PAGE_READWRITE)
+		if err != nil {
+			err = fmt.Errorf("Error allocating code: %w", err)
+			return
+		}
+	}
+	err = module.check4GBBoundaries(alignedImageSize)
+	if err != nil {
+		err = fmt.Errorf("Error reallocating code: %w", err)
+		return
+	}
+
+	if size < uintptr(oldHeader.OptionalHeader.SizeOfHeaders) {
+		err = errors.New("Incomplete headers")
+		return
+	}
+	// Commit memory for headers.
+	headers, err := windows.VirtualAlloc(module.codeBase,
+		uintptr(oldHeader.OptionalHeader.SizeOfHeaders),
+		windows.MEM_COMMIT,
+		windows.PAGE_READWRITE)
+	if err != nil {
+		err = fmt.Errorf("Error allocating headers: %w", err)
+		return
+	}
+	// Copy PE header to code.
+	memcpy(headers, addr, uintptr(oldHeader.OptionalHeader.SizeOfHeaders))
+	module.headers = (*IMAGE_NT_HEADERS)(a2p(headers + uintptr(dosHeader.E_lfanew)))
+
+	// Update position.
+	module.headers.OptionalHeader.ImageBase = module.codeBase
+
+	// Copy sections from DLL file block to new memory location.
+	err = module.copySections(addr, size, oldHeader)
+	if err != nil {
+		err = fmt.Errorf("Error copying sections: %w", err)
+		return
+	}
+
+	// Adjust base address of imported data.
+	locationDelta := module.headers.OptionalHeader.ImageBase - oldHeader.OptionalHeader.ImageBase
+	if locationDelta != 0 {
+		module.isRelocated, err = module.performBaseRelocation(locationDelta)
+		if err != nil {
+			err = fmt.Errorf("Error relocating module: %w", err)
+			return
+		}
+	} else {
+		module.isRelocated = true
+	}
+
+	// Load required dlls and adjust function table of imports.
+	err = module.buildImportTable()
+	if err != nil {
+		err = fmt.Errorf("Error building import table: %w", err)
+		return
+	}
+
+	// Mark memory pages depending on section headers and release sections that are marked as "discardable".
+	err = module.finalizeSections()
+	if err != nil {
+		err = fmt.Errorf("Error finalizing sections: %w", err)
+		return
+	}
+
+	// TLS callbacks are executed BEFORE the main loading.
+	module.executeTLS()
+
+	// Get entry point of loaded module.
+	if module.headers.OptionalHeader.AddressOfEntryPoint != 0 {
+		module.entry = module.codeBase + uintptr(module.headers.OptionalHeader.AddressOfEntryPoint)
+		if module.isDLL {
+			// Notify library about attaching to process.
+			r0, _, _ := syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), 0)
+			successful := r0 != 0
+			if !successful {
+				err = windows.ERROR_DLL_INIT_FAILED
+				return
+			}
+			module.initialized = true
+		}
+	}
+
+	module.buildNameExports()
+	return
+}
+
+// Free releases module resources and unloads it.
+func (module *Module) Free() {
+	if module.initialized {
+		// Notify library about detaching from process.
+		syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_DETACH), 0)
+		module.initialized = false
+	}
+	if module.modules != nil {
+		// Free previously opened libraries.
+		for _, handle := range module.modules {
+			windows.FreeLibrary(handle)
+		}
+		module.modules = nil
+	}
+	if module.codeBase != 0 {
+		windows.VirtualFree(module.codeBase, 0, windows.MEM_RELEASE)
+		module.codeBase = 0
+	}
+	if module.blockedMemory != nil {
+		module.blockedMemory.free()
+		module.blockedMemory = nil
+	}
+}
+
+// ProcAddressByName returns function address by exported name.
+func (module *Module) ProcAddressByName(name string) (uintptr, error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return 0, errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if module.nameExports == nil {
+		return 0, errors.New("No functions exported by name")
+	}
+	if idx, ok := module.nameExports[name]; ok {
+		if uint32(idx) > exports.NumberOfFunctions {
+			return 0, errors.New("Ordinal number too high")
+		}
+		// AddressOfFunctions contains the RVAs to the "real" functions.
+		return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
+	}
+	return 0, errors.New("Function not found by name")
+}
+
+// ProcAddressByOrdinal returns function address by exported ordinal.
+func (module *Module) ProcAddressByOrdinal(ordinal uint16) (uintptr, error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return 0, errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if uint32(ordinal) < exports.Base {
+		return 0, errors.New("Ordinal number too low")
+	}
+	idx := ordinal - uint16(exports.Base)
+	if uint32(idx) > exports.NumberOfFunctions {
+		return 0, errors.New("Ordinal number too high")
+	}
+	// AddressOfFunctions contains the RVAs to the "real" functions.
+	return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
+}
+
+func alignDown(value, alignment uintptr) uintptr {
+	return value & ^(alignment - 1)
+}
+
+func alignUp(value, alignment uintptr) uintptr {
+	return (value + alignment - 1) & ^(alignment - 1)
+}
+
+func a2p(addr uintptr) unsafe.Pointer {
+	return unsafe.Pointer(addr)
+}
+
+func memcpy(dst, src, size uintptr) {
+	var d, s []byte
+	unsafeSlice(unsafe.Pointer(&d), a2p(dst), int(size))
+	unsafeSlice(unsafe.Pointer(&s), a2p(src), int(size))
+	copy(d, s)
+}
+
+// unsafeSlice updates the slice slicePtr to be a slice
+// referencing the provided data with its length & capacity set to
+// lenCap.
+//
+// TODO: when Go 1.16 or Go 1.17 is the minimum supported version,
+// update callers to use unsafe.Slice instead of this.
+func unsafeSlice(slicePtr, data unsafe.Pointer, lenCap int) {
+	type sliceHeader struct {
+		Data unsafe.Pointer
+		Len  int
+		Cap  int
+	}
+	h := (*sliceHeader)(slicePtr)
+	h.Data = data
+	h.Len = lenCap
+	h.Cap = lenCap
+}